bazel,ci: propagate TEST_TMPDIR down to go tests and capture artifacts

This fulfills a long-standing request to capture left-over artifacts in
`TMPDIR` (see cockroachdb#59045 (comment)).

Bazel sets the `TEST_TMPDIR` environment variable for the temporary
directory and expects all tests to write temporary files to that
directory. In our Go tests, however, we consult the `TMPDIR` environment
variable to find that directory. So we pull in a custom change to
`rules_go` to copy `TEST_TMPDIR` to `TMPDIR`. Update `.bazelrc` to use
`/artifacts/tmp` as the `TEST_TMPDIR`.

Closes cockroachdb#59045.
Closes cockroachdb#69372.

Release justification: Non-production code change
Release note: None

.bazelrc

@@ -14,6 +14,7 @@ build:ci --host_crosstool_top=@toolchain_cross_x86_64-unknown-linux-gnu//:suite
 test:ci --test_env=GO_TEST_WRAP_TESTV=1
 # Dump all output for failed tests to the build log.
 test:ci --test_output=errors
+test:ci --test_tmpdir=/artifacts/tmp
 
 # cross-compilation configurations. Add e.g. --config=crosslinux to turn these on
 # TODO(ricky): Having to specify both the `platform` and the `crosstool_top` is

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 = "91c4e2b0f233c7031b191b93587f562ffe21f86f",
+    commit = "4a7bcc9b9051eb6a12bcb03a9bf38138c4bbc2ea",
     remote = "https://github.com/cockroachdb/rules_go",
 )