Reorganize wasi-misc-tests. (#575)

* Reorganize wasi-misc-tests.

Move wasi-misc-tests out of wasi-common, to break a dependency cycle;
previously, wasmtime-* depended on wasi-common, but wasi-common
dev-dependended on wasmtime-*.

Now, wasi-common no longer dev-depends on wasmtime-*; instead, the
tests are in their own crate which depends on wasi-common and on
wasmtime-*.

Also, rename wasi-misc-tests to wasi-tests for simplicity.

This also removes the "wasm_tests" feature; it's replaced by the
"test-programs" feature.

* Update the CI script to use the new feature name.

* Update the CI script to use the new feature name in one more place.

* Change a `write!` to a `writeln!`.

crates/test-programs/Cargo.toml

@@ -0,0 +1,24 @@
+[package]
+name = "test-programs"
+version = "0.0.0"
+authors = ["The Wasmtime Project Developers"]
+readme = "README.md"
+edition = "2018"
+publish = false
+
+[build-dependencies]
+cfg-if = "0.1.9"
+
+[dev-dependencies]
+wasi-common = { path = "../wasi-common" }
+wasmtime-runtime = { path = "../runtime" }
+wasmtime-environ = { path = "../environ" }
+wasmtime-jit = { path = "../jit" }
+wasmtime-wasi = { path = "../wasi" }
+wasmtime = { path = "../api" }
+cranelift-codegen = "0.50.0"
+target-lexicon = "0.9.0"
+pretty_env_logger = "0.3.0"
+tempfile = "3.1.0"
+os_pipe = "0.9"
+anyhow = "1.0.19"