testdata/runfiles_test/MODULE.mock pins to its own rules_cc rather than following the top level bazel choice

### Description of the bug:

src/test/py/bazel/testdata/runfiles_test/WORKSPACE.mock uses an ancient commit from rules_cc.
https://github.com/bazelbuild/rules_cc/commit/8bd6cd75d03c01bb82561a96d9c1f9f7157b13d0

We should generate this file from distdir_deps.bzl using gen_workspace_stanza. That will align the tests using this declaration with the other integration tests that use the rules_cc we build with.

The same problem exists in
- src/main/java/com/google/devtools/build/lib/bazel/rules/android/android_remote_tools.WORKSPACE
- tools/test/extensions.bzl

Start with distdir_deps.bzl and the gen_workspace_stanza mechanism, then inspect the listed WORKSPACE.mock, android_remote_tools.WORKSPACE, and tools/test/extensions.bzl files. Done means these declarations are generated from the top-level dependency choice and no longer pin the ancient rules_cc commit; verify the affected integration tests.

Written by the indexing model from the issue text.