alpkit: Add tests for generated JSON schemas #56

Job	Run time
Test with --features shell-timeout	35s
Test with --features flate2-zlib --no-default-features	29s
Test with --features flate2-zlib-ng --no-default-features	36s
Test on x86_64-alpine-linux-musl (dynamically linked)	1m 34s
Run linters	58s
Test on x86_64-unknown-linux-musl with Rust stable	30s
Test on x86_64-unknown-linux-musl with Rust nightly	1m 19s
Test on x86_64-unknown-linux-musl with Rust 1.64	2m 46s
Test on x86_64-unknown-linux-gnu with Rust stable	38s
Test on x86_64-apple-darwin with Rust stable	45s
Test on aarch64-unknown-linux-musl with Rust stable	2m 54s
Test on aarch64-unknown-linux-gnu with Rust stable	3m 1s
Test on armv7-unknown-linux-musleabihf with Rust stable	3m 4s
Test on powerpc64le-unknown-linux-gnu with Rust stable	2m 58s
Test on riscv64gc-unknown-linux-gnu with Rust stable	3m 2s
	25m 9s

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