Renamed subresource-integrity/support to "tools".

Also if https://github.com/w3c/web-platform-tests/pull/1492 hasn't been merged yet, then update that to reflect this name change. Otherwise, if https://github.com/w3c/web-platform-tests/pull/1492 has been merged, then update this to include the same name change to the corresponding item in `tools/scripts/lint.whitelist`.