Synthesize register classes for TRI::getMatchingSuperRegClass().

Teach TableGen to create the missing register classes needed for
getMatchingSuperRegClass() to return maximal results.  The function is
still not auto-generated, so it still returns inexact results.

This produces these new register classes:

ARM:
    QQPR_with_dsub_0_in_DPR_8
    QQQQPR_with_dsub_0_in_DPR_8
X86:
    GR64_with_sub_32bit_in_GR32_NOAX
    GR64_with_sub_32bit_in_GR32_NOAX_and_GR32_NOSP
    GR64_with_sub_16bit_in_GR16_NOREX
    GR64_with_sub_32bit_in_GR32_NOAX_and_GR32_NOREX
    GR64_TC_and_GR64_with_sub_32bit_in_GR32_NOAX
    GR64_with_sub_32bit_in_GR32_NOAX_and_GR32_NOREX_NOSP
    GR64_TCW64_and_GR64_with_sub_32bit_in_GR32_NOAX
    GR64_TC_and_GR64_with_sub_32bit_in_GR32_NOAX_and_GR32_NOREX
    GR64_with_sub_32bit_in_GR32_TC
    GR64_with_sub_32bit_in_GR32_ABCD_and_GR32_NOAX
    GR64_with_sub_32bit_in_GR32_NOAX_and_GR32_TC
    GR64_with_sub_32bit_in_GR32_AD
    GR64_with_sub_32bit_in_GR32_AD_and_GR32_NOAX

The other targets in the tree are not weird enough to be affected.

llvm-svn: 146872