RFR(s): 8205581: PPC64: RTM: Fix abort on native calls

[Gustavo Romero]

Hi,

Could the following change be reviewed please?

bug   : https://bugs.openjdk.java.net/browse/JDK-8205581
webrev: http://cr.openjdk.java.net/~gromero/8205581/v1/

It forces a transactional state to abort before calling native methods, before
calling runtime, and on uncommon trap checking, mostly because transaction will
be aborted soon or latter in either case, similarly to what happens on Intel.
The abort instruction (tabort) is only emitted if UseRTMLocking is "true" and
any 'tabort' instruction is treated as a 'nop' instruction if TM state is
non-transactional.

It fixes the following tests:

+Passed: compiler/rtm/print/TestPrintPreciseRTMLockingStatistics.java
+Passed: compiler/rtm/locking/TestRTMDeoptOnHighAbortRatio.java


Thank you and best regards,
Gustavo