Very small fix that removes fillInStackTrace from UnwarrantedOptimismException and RewriteException. All tests pass. This buys us a few single digit percent on avatar startup with Optimistic Types
Webrev at: http://cr.openjdk.java.net/~lagergren/8059123/webrev/ Bug at: https://bugs.openjdk.java.net/browse/JDK-8059123 /M
