[clang] Always execute multi-stage install steps

We want installs to be executed even if binaries haven't changed, e.g.
so that we can install to multiple places. This is consistent with how
non-multi-stage install targets (e.g. the regular install-distribution
target) behave.

Reviewed By: phosek

Differential Revision: https://reviews.llvm.org/D99321

GitOrigin-RevId: 0135bc996d82ff68677820c421b4d666590e4f31
1 file changed