8151956: Support non-continuous CodeBlobs in HotSpot
Reviewed-by: iveresov, thartmann, simonis

Merge

8136421: JEP 243: Java-Level JVM Compiler Interface
Reviewed-by: ihse, alanb, roland, coleenp, iveresov, kvn, kbarrett

8080775: Better argument formatting for assert() and friends
Reviewed-by: kbarrett, pliden

8061205: MetadataOnStackMark only needs to walk code cache during class redefinition
Summary: Only do full metadata walk during class redefinition and only walk handles during class unloading.
Reviewed-by: sspitsyn, stefank

8056240: Investigate increased GC remark time after class unloading changes in CRM Fuse
Reviewed-by: mgerdin, coleenp, bdelsart

8055008: Clean up code that saves the previous versions of redefined classes
Summary: Use scratch_class to find EMCP methods for breakpoints if the old methods are still running.
Reviewed-by: dcubed, sspitsyn

8049421: G1 Class Unloading after completing a concurrent mark cycle
Reviewed-by: tschatzl, ehelin, brutisso, coleenp, roland, iveresov
Contributed-by: stefan.karlsson@oracle.com, mikael.gerdin@oracle.com

8049420: Backout 8048248 to correct attribution
Reviewed-by: ehelin, brutisso

8048248: G1 Class Unloading after completing a concurrent mark cycle
Reviewed-by: tschatzl, ehelin, brutisso, coleenp, roland, iveresov

8027630: SIGSEGV in const char*Klass::external_name()
Reviewed-by: coleenp, sspitsyn, mgronlun

8026946: JvmtiEnv::SetBreakpoint and JvmtiEnv::ClearBreakpoint should use MethodHandle
8026948: JvmtiEnv::SetBreakpoint and JvmtiEnv::ClearBreakpoint might not work with anonymous classes
Summary: Walk methods in breakpoints for marking on stack so they aren't deallocated by redefine classes. Use class_holder rather than class_loader to keep GC from reclaiming class owning the method.
Reviewed-by: sspitsyn, ehelin, sla

8006040: NPG: on_stack processing wastes space in ConstantPool
Summary: Added on_stack bit to flags. Also MetadataMarkOnStack is used for more than JVMTI so had to be moved.
Reviewed-by: dholmes, stefank