fix: hard code mocha runner for pw-test #710

Job	Run time
check	1m 48s
test-electron-renderer	32s
test-chrome	47s
test-electron-main	50s
test-chrome-webworker	38s
test-firefox	42s
test-firefox-webworker	34s
test-node (windows-latest, lts/*)	3m 51s
test-node (ubuntu-latest, lts/*)	2m 27s
test-node (macos-latest, lts/*)	6m 58s
test-webkit (ubuntu-latest, lts/*)	20s
test-webkit (macos-latest, lts/*)	1m 55s
test-webkit-webworker (ubuntu-latest, lts/*)	20s
test-webkit-webworker (macos-latest, lts/*)	1m 27s
release	0s
	23m 9s

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