RFR: 8229971: ARM32: implementation for Thread-local handshakes

[Boris Ulasevich]

Hi,

Please review the implementation of Thread-local handshakes [1] support 
for ARM32. The implementation basically follows the similar update in 
aarch64 port [2].

http://cr.openjdk.java.net/~bulasevich/8229971/webrev.03
http://bugs.openjdk.java.net/browse/JDK-8229971

Tested with JTReg with no regressions in release mode (fastdebug mode 
testing is still in progress, but I am pretty sure it is Ok).

thanks,
Boris

[1] http://bugs.openjdk.java.net/browse/JDK-8185640
[2] 
http://mail.openjdk.java.net/pipermail/aarch64-port-dev/2017-November/005104.html