RFR(S): 8223249: [s390] Cleanup TemplateInterpreterGenerator::generate_fixed_frame

[Doerr, Martin]

Hi,

I'd like to simplify and improve the s390 implementation of generate_fixed_frame.
The current implementation of generate_fixed_frame unnecessarily reloads fields from memory. Most prominent is the reload of ConstMethod* (5 times).
In addition, unneeded monitor space is allocated in the top frame. Space for monitors gets added on demand (lock_method uses add_monitor_to_stack).
Also, implementation can get simplified by using MacroAssembler::Clear_Array.

Please review:
http://cr.openjdk.java.net/~mdoerr/8223249_s390_generate_fixed_frame/webrev.00/

Best regards,
Martin