RFR(L): 8220051: Remove global safepoint code

[Robbin Ehn]

Corrected mail-header.

/Robbin

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