bazel: stage all go source files in a temp dir named after the package

This works around an issue where Go source file names as stored in the
`cockroach` binary were truncated (e.g., with the leading
`github.com/cockroachdb/cockroach` prefix, or even the entire package
name prefix, removed). This breaks unit tests (#61913) and some other
internal stuff.

We solve this by staging all Go source files during the build in a
temporary directory named after the package. This incurs an additional
I/O cost, but for now while our codebase isn't able to deal with the
differing file names, we can deal with it.

Fixes #64379
See also #64383

Release note: None

WORKSPACE

@@ -12,7 +12,7 @@ load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
 # Load go bazel tools. This gives us access to the go bazel SDK/toolchains.
 git_repository(
     name = "io_bazel_rules_go",
-    commit = "2fe8a6256c818840cc9a10cf3f366d8410437245",
+    commit = "a94a425d26532613e71f9c7432c19c36302e1f1d",
     remote = "https://github.com/cockroachdb/rules_go",
 )