Revert r185557 as it was a bit (a lot) premature.
ARM: Prevent ARMAsmParser::shouldOmitCCOutOperand() from misidentifying certain Thumb2 add immediate T3 encodings.

Before the fix Thumb2 instructions of type "add rD, rN, #imm" (T3 encoding, see ARM ARM A8.8.4) with rD and rN both being low registers (r0-r7) were classified as having the T4 encoding.

The T4 encoding doesn't have a cc_out operand so for above instructions the operand gets erroneously removed, corrupting the token stream and leading to parse errors later in the process.

This bug prevented "add r1, r7, #0xcbcbcbcb" from being assembled correctly.

Fixes <rdar://problem/14224440>.