8064556: G1: ParallelGCThreads=0 may cause assert(!MetadataOnStackMark::has_buffer_for_thread(Thread::current())) failed: Should be empty
Reviewed-by: mgerdin, tschatzl

Reviewed-by: mgerdin, coleenp, bdelsart

Summary: Back-out 8052081 changes made in lcm.cpp.
Reviewed-by: iveresov, roland

Summary: Use mmap call without MAP_FIXED so we avoid corrupting already allocated memory
Reviewed-by: coleenp, dsimms

Summary: Fixed Whitebox.deoptimizeMethod() to deoptimize all OSR versions of the method.
Reviewed-by: kvn, iignatyev

Summary: Fixed 'SimpleThresholdPolicy::event' to always perform OSR if an OSR nmethod is available.
Reviewed-by: kvn, iveresov

Reviewed-by: jcoomes

Reviewed-by: dholmes, brutisso

Reviewed-by: coleenp, sspitsyn, jfranck

Summary: Implemented the interface in sun.misc.URLClassPath and corresponding JVM_XXX APIs
Reviewed-by: mchung, acorn, jiangli, dholmes

8061983: [TESTBUG] compiler/whitebox/MakeMethodNotCompilableTest.java fails with "must not be in queue"
Summary: Added a method checkNotCompiled(boolean isOsr) to either check if the method is OSR compiled or to check if it is non-OSR compiled.
Reviewed-by: kvn

Summary: Call warmup code from OSR triggering method to make sure no non-OSR compilation is triggered in the loop.
Reviewed-by: kvn

Summary: Move the call to 'waitAndDeoptimize' from the warmup methods to the osr triggering methods to make sure that no non-osr compilation is in the queue after warmup.
Reviewed-by: kvn

Summary: Added code to 'warm up' the methods before triggering OSR compilation by executing them a limited number of times. Like this, the profile information marks the loop exit as taken and we don't add an uncommon trap.
Reviewed-by: kvn, dlong, iignatyev