[asan] Add lit feature to indicate compiler_rt's shadow scale value

This will be used to mark tests that require a specific shadow scale.

Differential Revision: https://reviews.llvm.org/D39772

llvm-svn: 318469

compiler-rt/test/lit.common.cfg

@@ -320,3 +320,8 @@ elif config.android:
 # because the test hangs or fails on one configuration and not the other.
 if config.android or (config.target_arch not in ['arm', 'armhf', 'aarch64']):
   config.available_features.add('stable-runtime')
+
+if config.asan_shadow_scale:
+  config.available_features.add("shadow-scale-%s" % config.asan_shadow_scale)
+else:
+  config.available_features.add("shadow-scale-3")