Reland of "Avoid number range holes in bitset types."

This reverts commit 8a6cbf0a8632f39bc5bf740db672aa543e3e0f88.

R=rossberg@chromium.org
BUG=

Review URL: https://codereview.chromium.org/788313002

Cr-Commit-Position: refs/heads/master@{#25786}
[turbofan] Second round of optimisation for unordered comparisons on arm/arm64.

Avoid explicitly branching to the false label on unordered when the condition
on the true branch will not catch the unordered case and let the code fall
through.

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/794203003

Cr-Commit-Position: refs/heads/master@{#25787}