http_interop: Implement `Request` conversion for `http::request::Parts` #1693

Job	Run time
Lint	27s
cargo-deny (aarch64-apple-ios)	28s
Test	1m 12s
cargo-deny (aarch64-linux-android)	29s
Docs	50s
Test (json)	1m 10s
cargo-deny (i686-pc-windows-gnu)	28s
Test (charset)	1m 32s
cargo-deny (i686-pc-windows-msvc)	24s
Test (cookies)	1m 34s
cargo-deny (i686-unknown-linux-gnu)	28s
cargo-deny (wasm32-unknown-unknown)	26s
Test (socks-proxy)	1m 11s
cargo-deny (x86_64-apple-darwin)	30s
Test (native-certs)	1m 6s
cargo-deny (x86_64-apple-ios)	27s
Test (gzip)	1m 19s
cargo-deny (x86_64-pc-windows-gnu)	27s
Test (brotli)	1m 36s
cargo-deny (x86_64-pc-windows-msvc)	24s
Test (http-interop)	1m 10s
cargo-deny (x86_64-unknown-linux-gnu)	24s
Test (tls)	1m 35s
cargo-deny (x86_64-unknown-redox)	23s
Test (tls, json)	1m 30s
Test (tls, charset)	1m 27s
Test (tls, cookies)	1m 37s
Test (tls, socks-proxy)	1m 40s
Test (tls, native-certs)	1m 25s
Test (tls, gzip)	1m 18s
Test (tls, brotli)	1m 18s
Test (tls, http-interop)	1m 30s
Test (native-tls)	1m 16s
Test (native-tls, json)	1m 39s
Test (native-tls, charset)	1m 17s
Test (native-tls, cookies)	1m 49s
Test (native-tls, socks-proxy)	1m 18s
Test (native-tls, native-certs)	1m 28s
Test (native-tls, gzip)	1m 15s
Test (native-tls, brotli)	1m 26s
Test (native-tls, http-interop)	1m 37s
	44m 50s

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