RFR(L): Remove global safepoint code

[Erik Österlund]

Hi Robbin,

Was there any particular reason for changing the name of 
read_polling_page() on AArch64 to get_read_polling_page()?
It now sounds like tautology.

Otherwise this looks good, and I really like all the red lines. Dead 
code is the best code.

Thanks,
/Erik

On 2020-03-19 13:44, Robbin Ehn wrote:
> Hi all, please build, test and review.
>
> We removed (obsoleted) the flag ThreadLocalHandshakes in JDK 14.
> Any platform defining THREAD_LOCAL_POLL can only use per thread poll.
> Since all platforms now define THREAD_LOCAL_POLL the global poll code 
> is dead.
> Let's remove it!
>
> Issue: https://bugs.openjdk.java.net/browse/JDK-8220051
> Changeset: http://cr.openjdk.java.net/~rehn/8220051/v1/webrev/index.html
>
> I have built fastdebug:
> linux-aarch64
> linux-arm32
> linux-ppc64le
> linux-s390x
> linux-x86_64-zero
> linux-x86_64 (no PCH)
> linux-x86_64 (slowdebug) (no PCH)
> linux-x86
> osx-x86_64
> windows-x86_64
> solaris-sparcv9
>
> Tested t1-5:
> linux-x86_64
> osx-x86_64
> windows-x86_64
> solaris-sparcv9
>
> Manually:
> linux-aarch64
> linux-x86_64-zero
>
> Any extra help building and testing is appreciated, especially on 
> arm32, ppc64le, s390x.
>
> Thanks, Robbin