This is a mostly mechanical change that updates the JSTypedArray::length
field to have uintptr_t storage. It doesn't change the allowed ranges
for this field yet, that will be done separately later on.

Bug: v8:4153, v8:7881
Change-Id: Ia4b6f5455bd97b82a4b980d77bda0b09cfa845f5
Doc: http://doc/1Z-wM2qwvAuxH46e9ivtkYvKzzwYZg8ymm0x0wJaomow
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1607647
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61485}