rename and boolify some predicates for open intervals #479

Job	Run time
coq	55s
mathcomp-analysis-single	17m 33s
mathcomp	59s
mathcomp-classical	3m 7s
mathcomp-reals	4m 19s
mathcomp-reals-stdlib	1m 34s
mathcomp-analysis	14m 53s
mathcomp-experimental-reals	2m 6s
mathcomp-analysis-stdlib	15m 38s
ssprove	21m 17s
	1h 22m 21s

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