Add basic unittests for `CInifile` #4784

Job	Run time
Ubuntu Debug amd64 (gcc)	6m 31s
Windows Debug x64 (msvc)	8m 3s
Ubuntu Release amd64 (gcc)	6m 39s
Windows Debug x86 (msvc)	6m 25s
Ubuntu Debug amd64 (clang)	6m 53s
Windows Mixed x64 (msvc)	6m 9s
Ubuntu Release amd64 (clang)	9m 18s
Windows Mixed x86 (msvc)	5m 32s
Alpine Debug x86_64 (gcc)	7m 4s
Windows Release x64 (msvc)	10m 9s
Alpine Release x86_64 (gcc)	9m 5s
Windows Release x86 (msvc)	8m 45s
Alpine Debug x86 (gcc)	2m 13s
Windows Release Master Gold x64 (msvc)	9m 20s
Alpine Release x86 (gcc)	9m 20s
Windows Release Master Gold x86 (msvc)	10m 6s
Fedora Debug x86_64 (gcc)	18m 25s
Fedora Release x86_64 (gcc)	15m 39s
FreeBSD Debug x86_64	6m 50s
macOS Debug x86_64 (clang)	6m 45s
FreeBSD Release x86_64	9m 9s
macOS Release x86_64 (clang)	9m 53s
OpenBSD Debug x86_64	1s
macOS Debug arm64 (clang)	5m 5s
OpenBSD Release x86_64	9m 46s
macOS Release arm64 (clang)	7m 50s
NetBSD Debug x86_64	10m 18s
NetBSD Release x86_64	8m 41s
	3h 49m 54s

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