Avoid creating a throwaway raise exception

In particular, a long error message including the java stack trace was
being built and then discarded.
Improve Array#delete_if/reject! compatibility

Ensure that RubyArray#rejectBang fully updates the array at each step
of its iteration with a more direct port of MRI's array#ary_reject_bang

This requires more work than the previous implementation, but ensures
that the array is in the expected state if a user checks its contents
during the iteration, or breaks from the iteration early (as described
in https://bugs.ruby-lang.org/issues/2545)
Update to released version of jnr-posix
Turn off indy on all platforms by default.  It can still be manually enabled.  Added a note for next reconsideration point of re-enabling for JRuby 1.7.x
Merge pull request #1883 from dmarcotte/test-delete_if

Improve Array#delete_if/reject! compatibility
Merge pull request #1864 from grddev/rewrite-stacktrace-performance

Avoid creating a throwaway raise exception
Merge remote-tracking branch 'origin/jruby-1_7'

Conflicts:
	core/pom.xml
	core/src/main/java/org/jruby/runtime/Helpers.java
	test/mri/excludes/TestArray.rb