6681577: PIT: some VM tests fails with -XX:+AggressiveOpts in 6u5p b01
Summary: C2 spends > 60% in escape analysis code during test nsk/regression/b4675027.
Reviewed-by: never
6667042: PrintAssembly option does not work without special plugin
Summary: remove old private plugin interface, simplify, rework old plugin to use unchanged Gnu sources
Reviewed-by: kvn, rasbold