Currently, all autovectorization tests are spread all over the place:
test/hotspot/jtreg/compiler/loopopts/superword
test/hotspot/jtreg/compiler/vectorization/
test/hotspot/jtreg/compiler/c2/irTests/
etc.

We should move them all to the same directory, maybe with subdirectories:
test/hotspot/jtreg/compiler/autovectorization

This will give us a better overview, and would make it simpler to run all tests quickly over jtreg, by just specifying the directory.