This CL adds StoreFixedTypedArrayElementFromTagged to the CSA. This
method takes an array element in the form of a Number/BigInt, and
converts and stores it appropriately.
For BigInts, an existing method was refactored slightly to allow its
usage.
The added method is used in the upcoming Torque implementation
of TypedArray.p.sort.

R=jgruber@chromium.org

Bug: v8:7382
Change-Id: I5135de0eff96eb2048aaca73de327a027c1faef8
Reviewed-on: https://chromium-review.googlesource.com/1021083
Commit-Queue: Simon Zünd <szuend@google.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52711}