Add missing tracers for servo #398

Job	Run time
Integrity	22s
mac (--features debugmozjs)	16m 23s
mac	13m 48s
linux (--features debugmozjs)	9m 55s
linux	5m 44s
windows (--features debugmozjs)	15m 58s
windows (--features debugmozjs, aarch64-uwp-windows-msvc)	12m 42s
windows (--features debugmozjs, x86_64-uwp-windows-msvc)	11m 23s
windows	11m 26s
windows (aarch64-uwp-windows-msvc)	18m 47s
windows (x86_64-uwp-windows-msvc)	10m 46s
Result	1s
	2h 7m 15s

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