test: Clean up WebAssembly UI tests and update Karma configuration #1954

Job	Run time
Build (Unit-tests & Android-Lint)	6h 5m 0s
Android UI-tests on emulator (24, default)	2m 46s
Android UI-tests on emulator (28, default)	2m 48s
Android UI-tests on emulator (27, default)	4m 57s
Android UI-tests on emulator (25, default)	3m 3s
Android UI-tests on emulator (31, default)	2m 53s
Android UI-tests on emulator (29, default)	3m 3s
Android UI-tests on emulator (35, default)	2m 34s
Android UI-tests on emulator (23, default)	3m 12s
Android UI-tests on emulator (36, default)	3m 34s
Android UI-tests on emulator (33, default)	3m 10s
Android UI-tests on emulator (26, default)	4m 24s
Android UI-tests on emulator (32, default)	2m 55s
Android UI-tests on emulator (34, default)	3m 23s
Android UI-tests on emulator (30, default)	4m 49s
	6h 52m 31s

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