Implement fileinputstream::read and test #538

Job	Run time
rust_ci (macos-latest, beta)	19s
rust_ci (macos-latest, stable)	11s
rust_ci (macos-latest, nightly)	17s
rust_ci (windows-latest, stable)	11s
rust_ci (ubuntu-latest, stable)	13s
rust_ci (ubuntu-latest, beta)	15s
rust_ci (windows-latest, beta)	15s
rust_ci (windows-latest, nightly)	10s
rust_ci (ubuntu-latest, nightly)	15s
	2m 6s

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