RFR: 8061969 - [TESTBUG] MallocSiteHashOverflow.java should be enabled for 32-bit platforms

[George Triantafillou]

Please review this fix for JDK-8061969.  The test was modified to verify 
the fix for JDK-8058251, but since another intermittent issue was 
uncovered during testing (JDK-8062870), this test will retain the 
"@ignore" jtreg tag until the new issue is fixed.  Additionally, the 
"@requires" tag was used to ensure that the test only runs on 32-bit 
platforms.

Bug: https://bugs.openjdk.java.net/browse/JDK-8061969
Webrev: http://cr.openjdk.java.net/~gtriantafill/8061969/webrev/ 
<http://cr.openjdk.java.net/%7Egtriantafill/8061969/webrev/>

The fix was tested locally on Linux with jtreg and the JPRT hotspot testset.

-George