Fix FCI wfn_symmetry example (fix #1726); simplify the fci direct_spi… #1171

Job	Run time
linux-build (ubuntu-20.04, 3.8)	50m 52s
linux-build (ubuntu-20.04, 3.12)	44m 22s
linux-build-aarch64 (ubuntu-20.04, cp39-cp39)	7m 51s
macos-build (3.10)	22m 34s
	2h 5m 39s

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