jdk7u4-b20: HotSpot

[John Coomes]

hs23-b21 has been integrated into jdk7u4-b20.

http://hg.openjdk.java.net/jdk7u/jdk7u4/rev/1eae71787c33
http://hg.openjdk.java.net/jdk7u/jdk7u4/corba/rev/81a59f2d7ea4
http://hg.openjdk.java.net/jdk7u/jdk7u4/hotspot/rev/ad6f5eaa165e
http://hg.openjdk.java.net/jdk7u/jdk7u4/jaxp/rev/b08fa5f66572
http://hg.openjdk.java.net/jdk7u/jdk7u4/jaxws/rev/ee1f14434585
http://hg.openjdk.java.net/jdk7u/jdk7u4/jdk/rev/1a495432b42a
http://hg.openjdk.java.net/jdk7u/jdk7u4/langtools/rev/83b2485f2acb

SQE waived PIT for these fixes.

7158135: new hotspot build - hs23-b21
7159766: Tiered compilation causes performance regressions