[asan] Enable -asan-use-private-alias on Darwin/Mach-O, add test for ODR false positive with LTO (llvm part)
The '-asan-use-private-alias’ option (disabled by default) option is currently only enabled for Linux and ELF, but it also works on Darwin and Mach-O. This option also fixes a known problem with LTO on Darwin (https://github.com/google/sanitizers/issues/647). This patch enables the support for Darwin (but still keeps it off by default) and adds the LTO test case.
Differential Revision: https://reviews.llvm.org/D24292
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281470
91177308-0d34-0410-b5e6-
96231b3b80d8