Micro-benchmarks show speed improvements across the various types:

TypedArrays-JoinBigIntTypes                7246   8297  14.50%
TypedArrays-JoinBigIntTypes                7194   8637  20.06%
TypedArrays-JoinBigIntTypes                7258   8586  18.30%
TypedArrays-JoinFloatTypes                24461  28628  17.04%
TypedArrays-JoinFloatTypes                24523  29647  20.89%
TypedArrays-JoinFloatTypes                24419  29327  20.10%
TypedArrays-JoinIntTypes                  23378  33928  45.13%
TypedArrays-JoinIntTypes                  23333  34034  45.86%
TypedArrays-JoinIntTypes                  21653  34000  57.02%
TypedArrays-JoinWithSeparatorBigIntTypes   6620   7339  10.86%
TypedArrays-JoinWithSeparatorBigIntTypes   6566   7579  15.43%
TypedArrays-JoinWithSeparatorBigIntTypes   6631   7481  12.82%
TypedArrays-JoinWithSeparatorFloatTypes   18695  19670   5.22%
TypedArrays-JoinWithSeparatorFloatTypes   18518  20088   8.48%
TypedArrays-JoinWithSeparatorFloatTypes   18482  20193   9.26%
TypedArrays-JoinWithSeparatorIntTypes     17849  21482  20.35%
TypedArrays-JoinWithSeparatorIntTypes     17831  21578  21.01%
TypedArrays-JoinWithSeparatorIntTypes     17937  21578  20.30%

Drive-by: Removed unused CSA helper InternalArrayCreate.

Bug: v8:7624
Change-Id: I8e63815982439cfd2267417d03cd2b71b4b7a812
Reviewed-on: https://chromium-review.googlesource.com/c/1369330
Commit-Queue: Peter Wong <peter.wm.wong@gmail.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58167}