Add another test that the slower gcstress causes timeouts

Test 141-class-unload can also timeout due to gcstress making a
finalize function take longer causing a warning message to be printed.

Test: Treehugger
Bug: 111543628
Change-Id: I308cf2ff0a998ac0c0be1a63d552ebd205845dfc
diff --git a/test/knownfailures.json b/test/knownfailures.json
index 3033079..44a5c12 100644
--- a/test/knownfailures.json
+++ b/test/knownfailures.json
@@ -1016,7 +1016,7 @@
         "description" : ["Gcstress requires the ability to open at least one file which means this test fails when it runs out."]
     },
     {
-        "tests": ["530-checker-lse2"],
+        "tests": ["530-checker-lse2", "141-class-unload"],
         "variant": "gcstress",
         "bug": "b/111543628",
         "description" : ["Test seems to timeout when run with gcstress due to slower unwinding by libbacktrace"]