Revision r128665 added an optimization to make use of NEON multiplier

Revision r128665 added an optimization to make use of NEON multiplier
accumulator forwarding.  Specifically (from SVN log entry):

Distribute (A + B) * C to (A * C) + (B * C) to make use of NEON multiplier
accumulator forwarding:
vadd d3, d0, d1
vmul d3, d3, d2
=>
vmul d3, d0, d2
vmla d3, d1, d2

Make sure it catches cases where operand 1 is add/fadd/sub/fsub, which was
intended in the original revision.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133127 91177308-0d34-0410-b5e6-96231b3b80d8