[ubsan-minimal] Fix the x86_64h config check

Checking if config.target_arch is x86_64h doesn't work (the 'h' suffix
is dropped here, and I didn't account for that). Instead, check to see
if '-arch x86_64h' is in the cflags.

Tested on a pre-Haswell bot.

rdar://problem/34378605

llvm-svn: 313053

compiler-rt/test/ubsan_minimal/lit.common.cfg

@@ -34,7 +34,7 @@ if config.host_os not in ['Linux', 'FreeBSD', 'NetBSD', 'Darwin']: # TODO: Windo
   config.unsupported = True
 
 # Don't target x86_64h if the test machine can't execute x86_64h binaries.
-if config.target_arch == 'x86_64h' and 'x86_64h' not in config.available_features:
+if '-arch x86_64h' in target_cflags and 'x86_64h' not in config.available_features:
   config.unsupported = True
 
 config.available_features.add('arch=' + config.target_arch)