We change a bunch of static_cast to a cleaner and shorter brace
initialization. I did not change every use of static_cast in the files,
just those that relate to SIMD, so as to not cause churn in the
diff/blame.

Change-Id: I7e90c1b81f09a1e7a3ae7c9825db4fdbd21db919
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2159737Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67373}