[15] RFR (L): 8241436: C2: Factor out C2-specific code from MacroAssembler

[Vladimir Ivanov]

http://cr.openjdk.java.net/~vlivanov/8241436/webrev.00/
https://bugs.openjdk.java.net/browse/JDK-8241436

(The patch is built on top of 8240248 [1].)

MacroAssembler has C2-only declarations and the number is growing over time.

C1 and template interpreter already subclass MacroAssembler for their 
own needs (C1_MacroAssembler and InterpreterMacroAssembler respectively).

I propose to introduce C2_MacroAssembler, move C2-specific code there, 
and use it exclusively across C2 code base.

I took the liberty and refactored aarch64, arm32, ppc64, s390x code 
along the way. I did a cross-build, but I ask maintaners to verify that 
it doesn't break anything.

Testing: tier1-4, build (product+debug): 
linux-aarch64,linux-arm32,linux-ppc64le,linux-s390x,linux-x64,solaris-sparcv9

Thanks!

Best regards,
Vladimir Ivanov

[1] 8240248: Extend superword reduction optimizations for x86
     http://cr.openjdk.java.net/~sviswanathan/8240248/webrev.02/