test: rename `test-eventtarget-whatwg-*.js`
This renames some test filenames to align with the existing
parallel/test-whatwg-*.js
for consistency.
According to the comment in each file, they are seemingly manually
ported from the wpt dom/events
tests.
Refs: https://github.com/nodejs/node/pull/43461
Signed-off-by: Daeyeon Jeong daeyeon.dev@gmail.com