test: don't load axe.min (#4533)

Noticed this while trying to debug a test that we were loading
`axe.min.js` into the unit tests instead of using `axe.js`. This made
debugging impossible, so I'm just serving the file needed for the
[colorjs
test](https://github.com/dequelabs/axe-core/blob/develop/test/integration/full/patch/patch.mjs#L43)
instead of loading it for the entire test run.

No QA required

test/karma.conf.js

@@ -100,7 +100,7 @@ module.exports = function (config) {
         served: true
       },
       'axe.js',
-      'axe.min.js',
+      { pattern: 'axe.min.js', included: false, served: true },
       'test/testutils.js'
     ].concat(testPaths),
     proxies: {