Attempt to figure out AltHold issue #781

Job	Run time
build (base)	5m 40s
build (clang)	7m 0s
build-gcc-heli	5m 44s
autotest-heli (sitltest-heli)	9m 57s
autotest (sitltest-copter-tests1a)	15m 2s
autotest (sitltest-copter-tests1b)	14m 14s
autotest (sitltest-copter-tests1c)	16m 25s
autotest (sitltest-copter-tests1d)	16m 8s
autotest (sitltest-copter-tests1e)	16m 14s
autotest (sitltest-copter-tests2a)	13m 37s
autotest (sitltest-copter-tests2b)	37m 50s
	2h 37m 51s

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