7009641: Don't fail VM when CodeCache is full
Summary: Allocation in the code cache returns NULL instead of failing the entire VM
Reviewed-by: kvn, iveresov
8025088: Missing cases for JVM_CONSTANT_MethodHandleInError cause crash if debugger steps into error-tagged method handle
Summary: Need to refetch each method from InstanceKlass after all safepoints. Removed leaky PreviousVersionInfo code.
Reviewed-by: coleenp, sspitsyn