Add as_executable to CcToolchainInfo

[IljaKroonen]

Description of the feature request:

Like we have an ld_executable and an ar_executable on the CcToolchainInfo API, add an as_executable, which gives a string to the assembler executable.

Feature requests: what underlying problem are you trying to solve with this feature?

When calling the graalvm native-image executable, that executable does, in turn, call the compiler. The path to the compiler can be specified with an option. However, gcc then tries to call ld (which is fine because it is already present in the toolchain), followed by as, which is not exposed in the toolchain API.

Relevant issue here.

What operating system are you running Bazel on?

The graal rules support mac OS and linux.

Have you found anything relevant by searching the web?

This issue asks for the same thing on the legacy api. However, it's not clear why it was closed when the new API was introduced, since the new API seemingly also does not have it.

#5494

[scentini]

cc @oquenchil

[googleson78]

Also hitting this when trying to do remote builds.

[github-actions]

Thank you for contributing to the Bazel repository! This issue has been marked as stale since it has not had any activity in the last 1+ years. It will be closed in the next 90 days unless any other activity occurs or one of the following labels is added: "not stale", "awaiting-bazeler". Please reach out to the triage team (@bazelbuild/triage) if you think this issue is still relevant or you are interested in getting the issue resolved.

[googleson78]

bump