[aarch64-port-dev ] RFR(xs): Aarch64: ReservedStackAccess may leave stack guard in inconsistent state

[Andrey Petushkov]

Hi All,

Please review small fix for for the following problem: during execution of
ReservedStackAccess annotated method it might happen that reserved pages
are reguarded while yellow pages left unguarded. At the same time the state
of stack guard is recorded as fully protected (stack_guard_enabled).
Subsequent execution of ReservedStackAccess annotated method then may lead
to VM crash instead of mere StackOverflowError.
Reproduced with ReservedStackTestCompiler jtreg test on aarch32-jdk11 port
codebase. The bug seem to be apparent and exists in aarch64-port as well,
hence the review request.
The actual fix is in aarch64-specific code but the shared code is changed
as well to help to catch such bugs earlier in the future

the link http://cr.openjdk.java.net/~apetushkov/ReservedStackAccess/

Thanks,
Andrey