Both macros currently call a function with individual CHECKs, which
makes error messages only show that one part of the equality check (and
not the the actual float values), and hides the actual location of the
check.
This CL refactors this such that the actual value is shown (just as
with other CHECK_EQ macros) and it shows the right file name and line
number.

R=ahaas@chromium.org

Bug: v8:7570
Change-Id: I198e73c053178a09f14330a18069463760693f81
Reviewed-on: https://chromium-review.googlesource.com/1027879Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52832}