Post-JIT light cleanup of ExecutionEngine.h: edited comments about the JIT,
removed runJITOnFunction and isLazyCompilationDisabled.

Deleted CodeGen\MachineCodeInfo.h which was used by runJITOnFunction() only.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217193 91177308-0d34-0410-b5e6-96231b3b80d8