RFR: 8067713: Move clean_weak_method_links for redefinition out of class unloading

[Coleen Phillimore]

Summary: Do this work during class redefinition, only verify clean 
during class unloading in debug mode.

open webrev at http://cr.openjdk.java.net/~coleenp/8067713/
bug link https://bugs.openjdk.java.net/browse/JDK-8067713

Roland added tests for the original bugs

https://bugs.openjdk.java.net/browse/JDK-8038636
and
https://bugs.openjdk.java.net/browse/JDK-8040237

test/compiler/profiling/spectrapredefineclass/Launcher.javatest/compiler/profiling/TestSpecTrapClassUnloading.java

Ran jdk/test/java/lang/instrument tests, vm.quick.testlist, testbase vm.redefine.testlist (thanks to Serguei for creating this list) with -Xmixed,
-Xcomp and
-XX:+IgnoreUnrecognizedVMOptions -XX:-TieredCompilation -XX:-UseOnStackReplacement -XX:-BackgroundCompilation -XX:+UseTypeSpeculation -XX:TypeProfileLevel=222

Thanks,
Coleen