RFR (L) 7133093: Improve system dictionary performance

[coleen.phillimore at oracle.com]

Summary: Implement one dictionary per ClassLoaderData for faster lookup 
and removal during class unloading

See RFE for more details.

open webrev at http://cr.openjdk.java.net/~coleenp/7133093.01/webrev
bug link https://bugs.openjdk.java.net/browse/JDK-7133093

Tested with full "nightly" run in rbt, plus locally class loading and 
unloading tests:

jtreg hotspot/test/runtime/ClassUnload

jtreg hotspot/test/runtime/modules

jtreg hotspot/test/gc/class_unloading

make test-hotspot-closed-tonga FILTER=quick TEST_JOBS=4 
TEST=vm.parallel_class_loading

csh ~/testing/run_jck9  (vm/lang/java_lang)

runThese -jck - uses class loader isolation to run each jck test and 
unloads tests when done (at -gc:5 intervals)


Thanks,
Coleen