add support of HermitOS #408

Job	Run time
CheckTargets	1m 29s
Clippy	8s
Check (aarch64-apple-ios)	31s
Docs	30s
Check (aarch64-apple-tvos)	30s
MinimalVersions (ubuntu-latest)	24s
MinimalVersions (macos-latest)	32s
MSRV (ubuntu-latest)	12s
Check (aarch64-unknown-openbsd)	30s
MSRV (macos-latest)	30s
MinimalVersions (windows-latest)	44s
Check (arm64_32-apple-watchos)	30s
Nightly	20s
MSRV (windows-latest)	28s
Check (armv7-sony-vita-newlibeabihf)	30s
Check (sparcv9-sun-solaris)	29s
Rustfmt	5s
Sanitizer (address)	55s
Check (x86_64-pc-solaris)	38s
Test (ubuntu-latest)	50s
Check (x86_64-unknown-dragonfly)	29s
Sanitizer (leak)	47s
TestPoll	41s
Test (macos-latest)	58s
Check (x86_64-unknown-openbsd)	29s
Sanitizer (memory)	1m 46s
Test (windows-latest)	1m 32s
Sanitizer (thread)	52s
TestWakerPipe	29s
Passed	1s
	18m 49s

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