TestUDP: use ephemeral port

[kghost]

Problem

Fix TestUDP failure. The problem is triggered when multiple TestUDP (gcc/clang/mbedtls variant) is running concurrently, then their UDP port may conflict.

Change overview

In TestUDP, use ephemeral port instead of CHIP_PORT (5540)

Testing

Verified by unit-tests

[228/251] ACTION //src/transport/raw/t...//build/toolchain/linux:linux_x64_gcc)
FAILED: gen/src/transport/raw/tests/TestUDP_run.pw_pystamp 
python3 ../../third_party/pigweed/repo/pw_build/py/pw_build/python_runner.py --gn-root ../../ --current-path ../../src/transport/raw/tests --default-toolchain=//build/toolchain/linux:linux_x64_gcc --current-toolchain=//build/toolchain/linux:linux_x64_gcc --touch gen/src/transport/raw/tests/TestUDP_run.pw_pystamp --capture-output -- ../../third_party/pigweed/repo/pw_unit_test/py/pw_unit_test/test_runner.py --runner ../../third_party/pigweed/repo/targets/host/run_test --test tests/TestUDP
INF Test 1/1: [ RUN] TestUDP
ERR ../../third_party/pigweed/repo/targets/host/run_test exited with status 255
OUT [3685167]
'#0:','Test-CHIP-Udp'
'#2:','Setup                 ','PASSED'
[1631567899.867510][3685169:3685169] CHIP:IN: UDP::Init bind&listen port=5540
'#3:','Simple Init Test IPV4 ','PASSED'
[1631567899.867611][3685169:3685169] CHIP:IN: UDP::Init bind&listen port=5540
[1631567899.867640][3685169:3685169] CHIP:IN: TransportMgr initialized
CHIP node ready to service events
../../src/transport/raw/tests/TestUDP.cpp:155: assertion failed: "ReceiveHandlerCallCount == 1"
'#3:','Message Self Test IPV4','FAILED'
[1631567900.867263][3685169:3685169] CHIP:IN: UDP::Init bind&listen port=5540
'#3:','Simple Init Test IPV6 ','PASSED'
[1631567900.867330][3685169:3685169] CHIP:IN: UDP::Init bind&listen port=5540
[1631567900.867354][3685169:3685169] CHIP:IN: TransportMgr initialized
'#3:','Message Self Test IPV6','PASSED'
[1631567900.867482][3685169:3685175] CHIP:IN: Async DNS worker thread woke up.
[1631567900.867524][3685169:3685175] CHIP:IN: Async DNS worker thread exiting.
[1631567900.867531][3685169:3685174] CHIP:IN: Async DNS worker thread woke up.
[1631567900.867581][3685169:3685174] CHIP:IN: Async DNS worker thread exiting.
'#4:','Teardown              ','PASSED'
'#6:','1','4'
'#7:','1','17'
INF Test 1/1: [FAIL] TestUDP
[233/251] ACTION //src/app/tests:TestC...//build/toolchain/linux:linux_x64_gcc)
ninja: build stopped: subcommand failed.

[mlepage-google]

Issue #6947 was happening regularly for me, but with this change, it hasn't happened after half a dozen attempts.

[github-actions]

Size increase report for "nrfconnect-example-build" from 29e6bcd

File	Section	File	VM
chip-shell.elf	rodata	24	28
chip-shell.elf	text	24	24
chip-shell.elf	device_handles	8	8
chip-lock.elf	rodata	24	24
chip-lock.elf	text	24	24
chip-lock.elf	device_handles	8	8

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-shell.elf and ./pull_artifact/chip-shell.elf:

sections,vmsize,filesize
.debug_info,0,146
.debug_loc,0,113
.debug_line,0,99
.strtab,0,43
.debug_str,0,39
.symtab,0,32
.debug_frame,0,28
rodata,28,24
text,24,24
.debug_abbrev,0,15
.debug_aranges,0,8
.debug_ranges,0,8
device_handles,8,8
.shstrtab,0,-3

Comparing ./master_artifact/chip-lock.elf and ./pull_artifact/chip-lock.elf:

sections,vmsize,filesize
.debug_info,0,146
.debug_line,0,99
.debug_loc,0,81
.strtab,0,43
.debug_str,0,39
.symtab,0,32
.debug_frame,0,28
rodata,24,24
text,24,24
.debug_abbrev,0,15
.debug_aranges,0,8
.debug_ranges,0,8
device_handles,8,8
.shstrtab,0,1

[github-actions]

Size increase report for "esp32-example-build" from 29e6bcd

File	Section	File	VM
chip-temperature-measurement-app.elf	.flash.text	104	104
chip-temperature-measurement-app.elf	.flash.rodata	24	24
chip-all-clusters-app.elf	.flash.rodata	32	32
chip-all-clusters-app.elf	.flash.text	32	32
chip-bridge-app.elf	.flash.text	116	116
chip-bridge-app.elf	.flash.rodata	24	24
chip-shell.elf	.flash.text	100	100
chip-shell.elf	.flash.rodata	24	24
chip-lock-app.elf	.flash.text	108	108
chip-lock-app.elf	.flash.rodata	24	24

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-persistent-storage.elf and ./pull_artifact/chip-persistent-storage.elf:

sections,vmsize,filesize

Comparing ./master_artifact/chip-temperature-measurement-app.elf and ./pull_artifact/chip-temperature-measurement-app.elf:

sections,vmsize,filesize
.debug_line,0,176
.debug_info,0,158
.flash.text,104,104
.debug_loc,0,50
.strtab,0,43
.debug_str,0,40
.debug_frame,0,24
.flash.rodata,24,24
.symtab,0,16
.debug_aranges,0,8
.debug_ranges,0,8
.shstrtab,0,1
[Unmapped],0,-128

Comparing ./master_artifact/chip-all-clusters-app.elf and ./pull_artifact/chip-all-clusters-app.elf:

sections,vmsize,filesize
.debug_line,0,174
.debug_info,0,153
.debug_loc,0,48
.strtab,0,43
.debug_str,0,39
.flash.rodata,32,32
.flash.text,32,32
.debug_frame,0,28
.symtab,0,16
.debug_abbrev,0,15
.debug_aranges,0,8
.debug_ranges,0,8
.riscv.attributes,0,-1
.shstrtab,0,-3
[Unmapped],0,-64

Comparing ./master_artifact/chip-bridge-app.elf and ./pull_artifact/chip-bridge-app.elf:

sections,vmsize,filesize
.debug_line,0,176
.debug_info,0,158
.flash.text,116,116
.strtab,0,43
.debug_str,0,36
.debug_frame,0,24
.flash.rodata,24,24
.symtab,0,16
.debug_loc,0,10
.debug_aranges,0,8
.debug_ranges,0,8
.shstrtab,0,1
[Unmapped],0,-140

Comparing ./master_artifact/chip-ipv6only-app.elf and ./pull_artifact/chip-ipv6only-app.elf:

sections,vmsize,filesize

Comparing ./master_artifact/chip-shell.elf and ./pull_artifact/chip-shell.elf:

sections,vmsize,filesize
.debug_line,0,176
.debug_info,0,158
.flash.text,100,100
.strtab,0,43
.debug_str,0,40
.debug_loc,0,26
.debug_frame,0,24
.flash.rodata,24,24
.symtab,0,16
.debug_aranges,0,8
.debug_ranges,0,8
.shstrtab,0,1
[Unmapped],0,-124

Comparing ./master_artifact/chip-lock-app.elf and ./pull_artifact/chip-lock-app.elf:

sections,vmsize,filesize
.debug_line,0,176
.debug_info,0,158
.flash.text,108,108
.strtab,0,43
.debug_str,0,40
.debug_loc,0,30
.debug_frame,0,24
.flash.rodata,24,24
.symtab,0,16
.xt.prop._ZNK4chip4SpanIhE7SubSpanEjj,0,12
.debug_aranges,0,8
.debug_ranges,0,8
.xt.lit._ZNK4chip4SpanIhE7SubSpanEjj,0,8
.shstrtab,0,1
[Unmapped],0,-132

Comparing ./master_artifact/chip-pigweed-app.elf and ./pull_artifact/chip-pigweed-app.elf:

sections,vmsize,filesize