test: split tcp_proxy test into config test and data test

[lambdai]

Commit Message:
Split from #15053 that will introduce another group of tcp proxy test cases.

tcp_proxy_test.cc line drop from 2206 to 1036.
tcp_proxy_test compile time drop from 110s to 93s.

The test gain a little bit of parallelism by running independently
tcp_proxy_test: 16s
config_test: 8s

The overall bazel test //test/... slightly increased because we are generating 2 test binaries tcp_proxy_test and config_test.

Additional Description:
Risk Level: LOW
Testing: pure test refactor
Docs Changes:
Release Notes:
Platform Specific Features:
[Optional Runtime guard:]
[Optional Fixes #Issue]
[Optional Deprecated:]
[Optional API Considerations:]

[junr03]

@venilnoronha do you mind taking a first pass?

[venilnoronha]

Looks good, thanks!

[lambdai]

@envoyproxy/senior-maintainers

[lambdai]

Thank you @venilnoronha IIUC the next step is to be reviewed by a senior maintainer :)

[ggreenway]

Splitting config vs proxy tests makes sense to me.

/wait

[ggreenway]

I think this is compiling the .h file into a lib. Maybe this should be hdrs not srcs?

[lambdai]

This should be hdrs. Fixed and add the missing pragma once in this file.

[lambdai]

For cc_library rules, headers in hdrs comprise the public interface of the library and can be directly included both from the files in hdrs and srcs of the library itself as well as from files in hdrs and srcs of cc_* rules that list the library in their deps. Headers in srcs must only be directly included from the files in hdrs and srcs of the library itself. 

tcp_proxy_base.h should be in hdrs because it is explicitly included the envoy_cc_test target. It's interesting there was no error reported by bazel before the fix.