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ARROW-5100: [JS] Remove swap while collapsing contiguous buffers

Fixes https://issues.apache.org/jira/browse/ARROW-5100

Seems like this is a fairly rare edge case, but really perplexing when it happens. I saw it when manually creating Arrow Columns from data sliced out of an ArrayBuffer pool, and just so happened to get an overlapping + out-of-order set of buffers. I added a test case that demonstrates the issue too.

Description from the issue:
> We collapse contiguous Uint8Arrays that share the same underlying ArrayBuffer and have overlapping byte ranges. This was done to maintain true zero-copy behavior when using certain node core streams that use a buffer pool internally, and could write chunks of the same logical Arrow Message at out-of-order byte offsets in the pool.

> Unfortunately this can also lead to a bug where, in rare cases, buffers are swapped while writing Arrow Messages too. We could have a flag to indicate whether we think collapsing out-of-order same-buffer chunks is safe, but I'm not sure if we can always know that, so I'd prefer to take it out and incur the copy cost.

Author: ptaylor <paul.e.taylor@me.com>

Closes #4102 from trxcllnt/js/no-buffer-swap and squashes the following commits:

0aaf813d <ptaylor> ensure built asset names match the js version
2a5c5d51 <ptaylor> remove swap behavior from contiguous buffer collapse for safety