Fix dev server output #780

Job	Run time
Test Browser on macOS (safari, default)	1m 58s
Test Browser on macOS (safari, main)	54s
Test Browser on Linux (firefox, default)	1m 32s
Test Browser on Linux (chrome, disabled)	1m 3s
Test Browser on macOS (safari, disabled)	1m 8s
Test Build	49s
Test Browser on Linux (firefox, disabled)	1m 17s
Test Browser on Linux (firefox, main)	59s
Test Browser on Linux (chrome, main)	40s
Test Browser on Linux (chrome, default)	1m 16s
Test Shell (v8, main)	43s
Test Shell (spidermonkey, main)	45s
Test Shell (spidermonkey, disabled)	1m 55s
Test Shell (v8, default)	2m 48s
Test Shell (jsc, disabled)	1m 42s
Test Shell (spidermonkey, default)	5m 14s
Test Shell (jsc, default)	3m 1s
Test Shell (v8, disabled)	1m 34s
Test Shell (jsc, main)	39s
	29m 57s

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