[arm][darwin] Don't generate libcalls for wide shifts on Darwin
Similar to ceb801612a678bdffe7e7bf163bd0eed9c9b73a2.
Darwin doesn't always use compiler-rt, and so we can't assume that these
functions are available on arm.
arphaman on Jun 5 2020, 3:40 PM.Authored by
the shift_minsize test gets failed on ARM cross builder http://lab.llvm.org:8011/builders/llvm-clang-win-x-armv7l/builds/7712
c:\buildbot\as-builder-1\llvm-clang-win-x-armv7l\build\bin\llc.exe: error: : error: unable to get target for 'aarch64-apple-darwin', see --version and --triple.
Would you take care of it?