This is a purely cosmetic change to make the Number constructor
in the JSCallReducer easier to read.

Bug: v8:7904, v8:8015
Change-Id: Id3248dcf9c4e8111bb4f0418bfa6993630df74bb
Reviewed-on: https://chromium-review.googlesource.com/1196432Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55528}