[13] RFR (XS): 8218406: C1: Redundant nmethod dependency for private method is added

[Vladimir Ivanov]

http://cr.openjdk.java.net/~vlivanov/8218406/webrev.00/
https://bugs.openjdk.java.net/browse/JDK-8218406

JDK-6986483 [1] enabled limited CHA support for interface methods in C1. 
It uncovered a missing case in consequent code which add nmethod 
dependency: neither final nor private methods can be overridden, but it 
checks only for final ones. Thus a redundant dependency is added for 
private interface method call and it triggers an assert during 
dependency validation (ClassHierarchyWalker doesn't expect to see 
private methods).

The fix is to adjust the relevant check to avoid introducing nmethod 
dependency for private interface methods.

Testing: failing JCK tests, hs-precheckin-comp, tier1-5 (in progress).

Best regards,
Vladimir Ivanov

[1] https://bugs.openjdk.java.net/browse/JDK-6986483