RFR: JDK-8161495: Fix patching, that may be occured twice (because patching checked by jump presence, which remain after patching in aarch32)

[Andrey Petushkov]

Dear All,

The notorious patch from Anton Kozlov is indeed missing a few more lines in order to function properly. The logic should be added to protect from trying to patch the site again when it’s already patched. Unfortunately the shared code is impacted because the decision to patch is made there and in terms which are far too much platform dependent, and happen to be unsuitable for the scheme we have chosen.

The changes are by courtesy of Anton himself (I just happen need them in order to apply my v6k patch..)

http://cr.openjdk.java.net/~apetushkov/8161495/webrev/ <http://cr.openjdk.java.net/~apetushkov/8161495/webrev/>

Thanks,
Andrey