This patch checks the type of the lhs operand of a floating point
comparison for ARM, and commutes the operands if it is #0.0.  It allows
us to optimize a comparison with zero, as the vcmp instruction
accepts #0.0 as rhs operand.

Code before for "0.0 < 0.123":
------------------------------
movw ip, #29360
movt ip, #37224
movw r9, #31981
movt r9, #16319
vmov d0, ip, r9
mov ip, #0
vmov d1, ip, ip
vcmp.f64 d1, d0
vmrs APSR, FPSCR
bcc +12

Code after:
-----------
movw ip, #29360
movt ip, #37224
movw r9, #31981
movt r9, #16319
vmov d0, ip, r9
vcmp.f64 d0, #0.0
vmrs APSR, FPSCR
bgt +12

BUG=

Review URL: https://codereview.chromium.org/1361913003

Cr-Commit-Position: refs/heads/master@{#30911}