7020521: arraycopy stubs place prebarriers incorrectly
Summary: Rearranged the pre-barrier placement in arraycopy stubs so that they are properly called in case of chained calls. Also refactored the code a little bit so that it looks uniform across the platforms and is more readable.
Reviewed-by: never, kvn
^build/
^dist/
/nbproject/private/
^webrev