[9] RFR (M): 8149741: Don't refer to stub entry points by index in external_word relocations

[Vladimir Ivanov]

> Nice clean up!
Thanks, Vladimir.

Updated webrev:
   http://cr.openjdk.java.net/~vlivanov/8149741/webrev.01.index/

>
> Casts should be the same:
>
> (uintptr_t)target >= (uint)os::vm_page_size()
Fixed.

> Why in assembler_windows_x86.cpp you used NULL_WORD and not simple NULL?
> NULL_WORD is used for integer values and NULL for pointers
> which is this case.
Fixed.

Best regards,
Vladimir Ivanov