This patch removes uses of the Darwin ABI for PowerPC related test cases. This
is the first step in removing Darwin support from the POWER backend.
clang/test/CodeGen/darwin-ppc-varargs.c was deleted because it was a darwin/ppc
specific test case.
All other tests were updated to remove the darwin/ppc specific invocation.
Phabricator Review: https://reviews.llvm.org/D50989.
llvm-svn: 340770