test: split test-fs-watch-ignore-* #2858

Job	Run time
Build slim tarball	1m 39s
aarch64-linux: with shared libraries	1h 27m 6s
x86_64-darwin: with shared libraries	1h 26m 6s
aarch64-darwin: with shared libraries	2h 55m 17s
x86_64-linux: with shared libraries	2h 4m 2s
	7h 54m 10s

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