[9] RFR (M): 8059342 : Add test to cover JDK-8030976

[Filipp Zhinkin]

Hi all,

please review a new test on 8030976 (unstable_if trap).

The test simply execute a method with an "if" only one
of whose branches is always taken.
After that compilation log is analyzed in order to find
expected trap for appropriate bci.

In order to obtain correct bci number the tested method is
constructed using asmlib.

Bug-id: https://bugs.openjdk.java.net/browse/JDK-8059342
Webrev: http://cr.openjdk.java.net/~fzhinkin/8059342/webrev.00/
Testing: JPRT, manual & automated

Thanks,
Filipp.