TblGen/AsmMatcher: Add support for honoring instruction Requires<[]> attributes as part of the matcher.  - Currently includes a hack to limit ourselves to "In32BitMode" and "In64BitMode", because we don't have the other infrastructure to properly deal with setting SSE, etc. features on X86.
TblGen/AsmMatcher: Add support for honoring instruction Requires<[]> attributes as part of the matcher.
 - Currently includes a hack to limit ourselves to "In32BitMode" and "In64BitMode", because we don't have the other infrastructure to properly deal with setting SSE, etc. features on X86.

git-svn-id: a4a6f32337ebd29ad4763b423022f00f68d1c7b7@108677 91177308-0d34-0410-b5e6-96231b3b80d8

lodyagin/bare_cxx,lodyagin/bare_cxx,lodyagin/bare_cxx,lodyagin/bare_cxx,lodyagin/bare_cxx