Fix addrsig warnings

ld -r reorders symbols and invalidates the .llvm_addrsig section, which
then causes warnings if the resulting object is used with ld --icf=safe.
The warning is especially common when building with musl, as the
clang_rt.crt* objects have .llvm_addrsig sections, are linked into
libc_musl_crt* using ld -r, and are then linked into every other binary
and shared library with --icf=safe.

Strip the .llvm_addrsig section after ld -r to prevent the warnings.

Test: m USE_HOST_MUSL=true host-native -k
Change-Id: Ia52a4756b9ebbb62115898d0de9f8641e6fea705