Revert "Hide mutated variant in non-make builds."

This reverts commit 6147c697.

Rationale: first in group of commits that left aosp_x86_64 not
building. (See https://android-build.googleplex.com/builds/
submitted/4426589/aosp_x86_64-eng/latest/logs/build_error.log)

Bug: 30227045
Test: builds
Change-Id: I632869d13d09b43e2040da187d7ced4f05c332de