[sanitizer] Enable tsan for aarch64

[zatrazz]

Summary

This patch enables the -fsanitizer=thread option for Linux/aarch64.

[rengolin]

This patch is necessary for the RT tests to compile on AArch64.

[rengolin]

r244091

lib/Driver/ToolChains.cpp

SanitizerMask Linux::getSupportedSanitizers() const {
   const bool IsAArch64 = getTriple().getArch() == llvm::Triple::aarch64 ||
                          getTriple().getArch() == llvm::Triple::aarch64_be;
   SanitizerMask Res = ToolChain::getSupportedSanitizers();
   Res |= SanitizerKind::Address;
   Res |= SanitizerKind::KernelAddress;
   Res |= SanitizerKind::Vptr;
   if (IsX86_64 || IsMIPS64 || IsAArch64)
     Res |= SanitizerKind::DataFlow;
-  if (IsX86_64 || IsMIPS64) {
+  if (IsX86_64 || IsMIPS64)
     Res |= SanitizerKind::Leak;
+  if (IsX86_64 || IsMIPS64 || IsAArch64)
     Res |= SanitizerKind::Thread;
-  }
   if (IsX86_64 || IsMIPS64 || IsPowerPC64)
     Res |= SanitizerKind::Memory;
   if (IsX86 || IsX86_64) {
     Res |= SanitizerKind::Function;
     Res |= SanitizerKind::SafeStack;
   }
   return Res;
 }