X86JITInfo: [x86] Use X86CompilationCallback_SSE() along;

  *not* Subtarget->hasSSE1()
  *but* __SSE__, the flag that LLVM libraries are compiled

The callback calls internal LLVM JIT libraries. It may be built with -msse (or above).

FIXME: JIT may use "host" instead of "generic" by default.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206240 91177308-0d34-0410-b5e6-96231b3b80d8
[MC] Require an MCContext when constructing an MCDisassembler.

This patch re-introduces the MCContext member that was removed from
MCDisassembler in r206063, and requires that an MCContext be passed in at
MCDisassembler construction time. (Previously the MCContext member had been
initialized in an ad-hoc fashion after construction). The MCCContext member
can be used by MCDisassembler sub-classes to construct constant or
target-specific MCExprs.

This patch updates disassemblers for in-tree targets, and provides the
MCRegisterInfo instance that some disassemblers were using through the
MCContext (previously those backends were constructing their own
MCRegisterInfo instances).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206241 91177308-0d34-0410-b5e6-96231b3b80d8