Fix e10 butteraugli iterations (#3910) #668

Job	Run time
Ubuntu Build release	16m 55s
Ubuntu Build debug	15m 21s
Ubuntu Build asan	51m 27s
Ubuntu Build msan	1h 16m 50s
Ubuntu Build tsan	1h 3m 3s
Ubuntu Build scalar	15m 26s
Ubuntu Build lowprecision	17m 7s
Ubuntu Build coverage	2h 38m 59s
Ubuntu Build release-nojpeg	14m 8s
Ubuntu Build release-lcms2	14m 5s
Ubuntu Build release-system-lcms2	13m 58s
Ubuntu Build release:minimal	13m 50s
Ubuntu Build release:gcc8	13m 22s
Ubuntu Build release:clang-7	14m 30s
MacOS Build release:osx	8m 20s
	8h 27m 21s

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