Fix isInfixOf and breakSubString in Word16 #182

Job	Run time
arm (arm32v7)	6m 16s
arm (arm64v8)	4m 59s
i386	8m 34s
build (ubuntu-latest, 8.0.2, 3.8.1.0)	14m 40s
build (ubuntu-latest, 8.2.2, 3.8.1.0)	7m 46s
build (ubuntu-latest, 8.4.4, 3.8.1.0)	6m 30s
build (ubuntu-latest, 8.6.5, 3.8.1.0)	6m 34s
build (ubuntu-latest, 8.8.4, 3.8.1.0)	6m 32s
build (ubuntu-latest, 8.10.7, 3.8.1.0)	7m 50s
build (ubuntu-latest, 9.0.2, 3.8.1.0)	7m 18s
build (ubuntu-latest, 9.2.7, 3.8.1.0)	5m 25s
build (ubuntu-latest, 9.4.5, 3.8.1.0)	5m 17s
build (ubuntu-latest, 9.6.1, 3.8.1.0)	8m 58s
build (macOS-latest, 9.4.5, 3.8.1.0)	10m 46s
build (macOS-latest, 9.6.1, 3.8.1.0)	14m 35s
build (windows-latest, 9.4.5, 3.8.1.0)	45m 34s
build (windows-latest, 9.6.1, 3.8.1.0)	24m 21s
darwin_arm (self-hosted, macOS, ARM64, 8.10.7)	24m 7s
darwin_arm (self-hosted, macOS, ARM64, 9.2.6)	8m 44s
darwin_arm (self-hosted, macOS, ARM64, 9.4.4)	1h 4m 13s
	4h 48m 59s

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