Turns out that these subtests are the only pair which cannot run in
parallel with each other. Undo that change and add a TODO. This should
fix the CI failures.
While at it, remove an unnecessary testAllocate line.
The subtests were almost all marked as parallel, but that's not enough.
That only makes the subtests run in parallel with other subtests within
the same tests, not with any other test.
Since none of the tests make use of globals nor require the entire
program to themselves, properly run all the tests in parallel.
Speeds up 'go test' on my 8-core laptop from an average of ~130s to an
average of ~50s. Many tests hit timeouts and have sleeps, so we want to
avoid running those sequentially whenever possible.
Added high level action SetUploadFiles to set the upload files for a
input[type="file"] node, and modified SendKeys to recognize the nodes.
Additionally, added unit test for both, and updated the
examples/upload/main.go to use the SendKeys variant.
