Move the InsertPrologEpilogCode class out of the Sparc.cpp file into the

new PrologEpilogCodeInserter.cpp file, and include the bodies of the
GetInstructionsFor(Prolog|Epilog) functions from SparcInstrSelection.cpp
into the class.  This eliminates the need for a static global vector of
instructions and a class of errors that is really unneccesary.

llvm-svn: 2194