Eliminate the large XXXSubRegTable constant arrays.
Eliminate the large XXXSubRegTable constant arrays.

These tables were indexed by [register][subreg index] which made them,
very large and sparse.

Replace them with lists of sub-register indexes that match the existing
lists of sub-registers. MCRI::getSubReg() becomes a very short linear
search, like getSubRegIndex() already was.

git-svn-id: a4a6f32337ebd29ad4763b423022f00f68d1c7b7@160843 91177308-0d34-0410-b5e6-96231b3b80d8

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