fix(browser): handle config.base (#4686) #7196

Job	Run time
lint	1m 13s
lint	1m 13s
test-browser (chrome, chromium)	3m 0s
test-browser (chrome, chromium)	4m 21s
test-browser-windows (chrome, chromium)	6m 34s
test-browser-windows (chrome, chromium)	6m 9s
test-browser (firefox, firefox)	3m 7s
test-browser (firefox, firefox)	3m 1s
test (ubuntu-latest, 18)	10m 16s
test (ubuntu-latest, 18)	10m 16s
test-browser-windows (edge, webkit)	6m 38s
test-browser-windows (edge, webkit)	6m 38s
test-ui	1m 18s
test-ui	1m 18s
test-browser (edge, webkit)	3m 17s
test-browser (edge, webkit)	3m 50s
test (ubuntu-latest, 20)	10m 4s
test (ubuntu-latest, 20)	10m 4s
test (macos-latest, 20)	9m 1s
test (macos-latest, 20)	9m 39s
typecheck	2m 3s
typecheck	2m 3s
test (windows-latest, 20)	13m 28s
test (windows-latest, 20)	14m 38s
	2h 23m 9s

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