Previously, the basis of constant pooling was implemented, but two things were lacking:

1. The constant pools were not being emitted in the asm file.

2. A direct FP value was emitted in an FP instruction, e.g. "addss xmm0, 1.0000e00".  Curiously, at least for some FP constants, llvm-mc was accepting this syntax.

BUG= none
R=jfb@chromium.org

Review URL: https://codereview.chromium.org/291213003