update StringMap and test for StringMap #217

Job	Run time
test-gcc-mingw-w64-x86_64-posix-on-ubuntu-22.04	2m 42s
test-gcc-mingw-w64-i686-posix-on-ubuntu-22.04	1m 20s
test-gcc-on-ubuntu-20.04	5m 13s
test-gcc-mingw-w64-x86_64-posix-on-ubuntu-24.04	5m 12s
test-clang-on-ubuntu-20.04	1m 32s
test-gcc-mingw-w64-i686-posix-on-ubuntu-24.04	4m 6s
test-gcc-on-ubuntu-22.04	5m 12s
test-clang-on-ubuntu-22.04	5m 12s
test-gcc-on-ubuntu-24.04	5m 12s
test-clang-on-ubuntu-24.04	5m 12s
	40m 53s

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