RFR (XS) JDK-6961433: Revisit need to disable Windows C++ compiler optimisation of sharedRuntimeTrig.cpp

[Lois Foltan]

Hello,

Please review the following fix:

Webrev:
     http://cr.openjdk.java.net/~lfoltan/bug_jdk6961433/

Bug: Revisit need to disable Windows C++ compiler optimisation of 
sharedRuntimeTrig.cpp
     https://bugs.openjdk.java.net/browse/JDK-6961433

Summary of fix:
Remove WIN32 specific pragma optimize "off" within sharedRuntimeTrig.cpp 
which resulted in the file being compiled with no optimizations.  The 
SAFEBUF macro definition is also being removed.  It was a workaround 
caused by the pragma being in effect. The problem report indicates that 
this pragma was added in the VS2003/VS2005 time frame.  Where or how the 
C++ compiler optimization manifested itself could not be located.  Thank 
you to Dan Daugherty for completing a historical search to try to track 
this down.  His search is posted in the problem report.  Also, thank you 
to Vladimir Koslov for proposing ideas on how this should be tested.  
Since VS2010 & higher should not have this optimization issue, the 
pragma is being removed early in JDK 9 so it can benefit from continual 
full testing.

Tests:
JPRT build & test
vm.quick.testlist via Adhoc Aurora testing on Windows 32 & 64 bit - runs 
with/without -Xint
JDK java/lang & java/util - runs with/without -Xint
Hotspot JTREG - runs with/without -Xint
Built full JDK 9 fastdebug and production images with this Hotspot 
change, resulting image used for testing.