JDK 9 RFR of JDK-8154911: Move GCDuringIteration.java back to tier1

[Amy Lu]

java/util/WeakHashMap/GCDuringIteration.java

This test was failing intermittently (JDK-6842353) and demoted to tier2. 
Mentioned issues have been resolved and no open bug (no failure 
reported) till now.

This patch is to move the test back to tier1.

bug: https://bugs.openjdk.java.net/browse/JDK-8154911
webrev: http://cr.openjdk.java.net/~amlu/8154911/webrev.00/

Thanks,
Amy


--- old/test/TEST.groups	2016-04-25 10:54:59.000000000 +0800
+++ new/test/TEST.groups	2016-04-25 10:54:58.000000000 +0800
@@ -29,7 +29,6 @@
      :jdk_lang \
      -java/lang/ProcessHandle/TreeTest.java \
      :jdk_util \
-    -java/util/WeakHashMap/GCDuringIteration.java \
      -java/util/concurrent/ThreadPoolExecutor/ConfigChanges.java \
      -java/util/concurrent/forkjoin/FJExceptionTableLeak.java \
      sun/nio/cs/ISO8859x.java \
@@ -39,7 +38,6 @@
  
  tier2 = \
      java/lang/ProcessHandle/TreeTest.java \
-    java/util/WeakHashMap/GCDuringIteration.java \
      java/util/concurrent/ThreadPoolExecutor/ConfigChanges.java \
      java/util/concurrent/forkjoin/FJExceptionTableLeak.java \
      :jdk_io \