karma vue-test-utils setWatcherSync overflow

From https://gitlab.com/gitlab-org/gitlab-ee/-/jobs/191840178:

FAILED TESTS:
  urlComponent
    ✖ should render correctly
      Chrome
    RangeError: Maximum call stack size exceeded
        at setDepsSync (webpack:///builds/gitlab-org/gitlab-ee/node_modules/@vue/test-utils/dist/vue-test-utils.js:2007 <- spec/javascripts/test_bundle.bundle.js:714799:22)
        at Array.forEach (<anonymous>)
        at setWatcherSync (webpack:///builds/gitlab-org/gitlab-ee/node_modules/@vue/test-utils/dist/vue-test-utils.js:2016 <- spec/javascripts/test_bundle.bundle.js:714808:16)
        at Array.forEach (<anonymous>)
        at setDepsSync (webpack:///builds/gitlab-org/gitlab-ee/node_modules/@vue/test-utils/dist/vue-test-utils.js:2008 <- spec/javascripts/test_bundle.bundle.js:714800:12)
        at Array.forEach (<anonymous>)
        at setWatcherSync (webpack:///builds/gitlab-org/gitlab-ee/node_modules/@vue/test-utils/dist/vue-test-utils.js:2016 <- spec/javascripts/test_bundle.bundle.js:714808:16)
        at Array.forEach (<anonymous>)
        at setDepsSync (webpack:///builds/gitlab-org/gitlab-ee/node_modules/@vue/test-utils/dist/vue-test-utils.js:2008 <- spec/javascripts/test_bundle.bundle.js:714800:12)
        at Array.forEach (<anonymous>)
        at setWatcherSync (webpack:///builds/gitlab-org/gitlab-ee/node_modules/@vue/test-utils/dist/vue-test-utils.js:2016 <- spec/javascripts/test_bundle.bundle.js:714808:16)
        at Array.forEach (<anonymous>)
        at setDepsSync (webpack:///builds/gitlab-org/gitlab-ee/node_modules/@vue/test-utils/dist/vue-test-utils.js:2008 <- spec/javascripts/test_bundle.bundle.js:714800:12)
        at Array.forEach (<anonymous>)
        at setWatcherSync (webpack:///builds/gitlab-org/gitlab-ee/node_modules/@vue/test-utils/dist/vue-test-utils.js:2016 <- spec/javascripts/test_bundle.bundle.js:714808:16)

This looks like it came from https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9959.

/cc: @mikegreiling, @cab105