pkg/proc: add inline function support for stripped binaries (#3549)

This patch adds support for listing and setting breakpoints on inlined functions within stripped binaries. It uses a forked version of `debug/gosym` copied from golang.org/x/vuln/internal/vulncheck/internal/gosym which adds support for parsing the inline tree of the pclntab section. Parsing this section requires knowing the offset of the "go:func.*" symbol, which is not present in stripped binaries via the ``.symtab` section so instead, we search the `.noptrdata` section which contains `runtime.moduledatap` which contains the value of that missing symbol, which we then can use to find the inline tree for a given function.

Given all this we parse the inline tree for each function we find, and then add that information the the appropriate `Function` contained in `bi.Functions`, using a relatively empty `Function` struct as what would be the abstract origin.

Documentation/backend_test_health.md

@@ -17,9 +17,10 @@ Tests skipped by each supported backend:
 	* 2 follow exec not implemented on freebsd
 	* 4 not implemented
 	* 1 not working on freebsd
-* linux/386/pie skipped = 2
+* linux/386 skipped = 1
+	* 1 not working on linux/386
+* linux/386/pie skipped = 1
 	* 1 broken
-	* 1 not working on linux/386 with PIE
 * linux/ppc64le skipped = 2
 	* 1 broken - cgo stacktraces
 	* 1 not working on linux/ppc64le when -gcflags=-N -l is passed

_fixtures/inlinestripped.go

@@ -0,0 +1,15 @@
+package main
+
+import "fmt"
+
+func callme(i int) int {
+	return i * i
+}
+
+func main() {
+	j := 0
+	j += callme(2)
+	fmt.Println(j)
+	fmt.Println(j + 1)
+	fmt.Println(j + 2)
+}