The %target-cpu annotations here cause us to form the triple
arm64_32-unknown-linux-gnu which is not a valid triple. We don't need to
run these tests on arm64_32 platforms anyways.
rdar://77398372
This commit adds -lto flag for frontend to enable LTO at LLVM level.
When -lto=llvm given, compiler emits LLVM bitcode file instead of object
file and adds index summary for LTO.
In addition for ELF format, emit llvm.dependent-libraries section to
embed auto linking information
