Request for reviews (M): 6934966: JSR 292 add C1 logic for saved SP over MethodHandle calls

[Christian Thalinger]

http://cr.openjdk.java.net/~twisti/6934966/webrev.01/

The logic for x86 C1 to save the SP over MH calls is pretty straight
forward which uses the always-callee-saved BP register. On SPARC, and
maybe other architectures, we need to choose one of the callee-saved
registers and kill it over MH calls.

This CR adds some logic to support this. It should be pushed before
SPARC C1 support is pushed since that would break x86 C1.

src/cpu/sparc/vm/c1_LIRAssembler_sparc.cpp
src/cpu/sparc/vm/c1_LIRGenerator_sparc.cpp
src/cpu/x86/vm/c1_LIRAssembler_x86.cpp
src/cpu/x86/vm/c1_LIRGenerator_x86.cpp
src/share/vm/c1/c1_LIR.cpp
src/share/vm/c1/c1_LIR.hpp
src/share/vm/c1/c1_LIRAssembler.cpp
src/share/vm/c1/c1_LIRAssembler.hpp
src/share/vm/c1/c1_LIRGenerator.hpp
src/share/vm/includeDB_compiler1