I had to adjust Float64Max/Min on x64 slightly to return the default
wasm NaN (0x7FF0000000000000) instead of the all-ones NaN
(0xFFFFFFFFFFFFFFFF).

R=titzer@chromium.org, bmeurer@chromium.org

Review-Url: https://codereview.chromium.org/2204963002
Cr-Commit-Position: refs/heads/master@{#38410}