When bzlmod is enabled and WORKSPACE.bzlmod exists, the content of
WORKSPACE is ignored. This prevents bzlmod builds from unintentionally
depending on the WORKSPACE file.

This exposed some small problems with our clang-cl configuration,
which are also fixed in this change.

PiperOrigin-RevId: 602511311
Change-Id: I0ba411edde2df0e17f4eeede4117ddb6934dd8f8