RFR(S): 8210676: Remove some unused Label variables

[Mikael Vidstedt]

Please review this change which removes a bunch of unused Label variables. Would appreciate some help from aarch64/ppc/s390x folks to verify it!

bug: https://bugs.openjdk.java.net/browse/JDK-8210676
webrev: http://cr.openjdk.java.net/~mikael/webrevs/8210676/webrev.03/open/webrev/

* Background (from bug)

[~dholmes] noticed during the code review of JDK-8210381 that the "Label Egress" variable in macroAssembler_sparc.cpp was unused. It and other unused labels like it should be removed.

* About the change

I have *not* tried to find and remove *all* unused Label variables, because that turns out to be much harder than it might seem. I may or may not follow up on this work to remove additional unused Label variables later, but before that I’m investigating removal of other unused variables in general. Meanwhile I like to think that this is a reasonable cleanup anyway.

* Testing

tier1 build&test passes.

Cheers,
Mikael