RFR 8206423: Use ConcurrentHashTable for ResolvedMethodTable

[Patricio Chilano]

Hi all,
Could you review this fix that moves the cleanup up of dead entries in 
the resolved method table from the VMThread to the ServiceThread.
The goal was to remove the need to clean up dead entries in the resolved 
method table during safepoints, thus reducing pause times. That task was 
moved to the ServiceThread, which will be notified by the VMThread when 
detecting the need to cleanup after class unloading. Benchmarks where 
run(javac, sanity, SPECjbb) showing non-significant results.
The fix was tested with Mach5 on tiers 1, 2, 3 on all platforms. (Note: 
test/hotspot/jtreg/runtime/MemberName/MemberNameLeak.java already exists 
and tests the creation and deletion of entries in the resolved method 
table).
Bug URL: https://bugs.openjdk.java.net/browse/JDK-8206423
Webrev URL: 
http://cr.openjdk.java.net/~coleenp/8206423.01/webrev/index.html 
<http://cr.openjdk.java.net/%7Ecoleenp/8206470.01/webrev/index.html>
Thanks,
Patricio