Un-blacklist 080-oom-fragmentation for non-GSS configurations.

080-oom-fragmentation test fails with GSS GC due to lack of support for
allocations larger than 32MB even with a larger max heap size.

Test: test/testrunner/testrunner.py
Bug: 33795328
Change-Id: I9b3f323149dcd2a74626275051023c25d4625f58
diff --git a/test/knownfailures.json b/test/knownfailures.json
index f0b88e9..426bbaf 100644
--- a/test/knownfailures.json
+++ b/test/knownfailures.json
@@ -13,7 +13,9 @@
     },
     {
         "tests": "080-oom-fragmentation",
-        "description": "Disable 080-oom-fragmentation due to flakes.",
+        "description": ["Disable 080-oom-fragmentation for GSS GC due to lack of",
+		        "support for allocations larger than 32MB."],
+	"env_vars": {"ART_DEFAULT_GC_TYPE": "GSS"},
         "bug": "http://b/33795328"
     },
     {