[tests] Accept XFAIL arguments that match any part of a feature.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@174469 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/lit.cfg b/test/lit.cfg
index 0c74a7d..d48872c 100644
--- a/test/lit.cfg
+++ b/test/lit.cfg
@@ -21,9 +21,10 @@
         if item == '*':
             return True
 
-        # If this is an exact match for one of the features, it fails.
-        if item in test.config.available_features:
-            return True
+        # If this is a part of any of the features, it fails.
+        for feature in test.config.available_features:
+            if item in feature:
+                return True
 
         # If this is a part of the target triple, it fails.
         if item in test.suite.config.target_triple: