Fixes for 0.15 (#1449)

* Wasmtime 0.15.0 and Cranelift 0.62.0. (#1398)

* Bump more ad-hoc versions.

* Add build.rs to wasi-common's Cargo.toml.

* Update the env var name in more places.

* Remove a redundant echo.

crates/test-programs/wasi-tests/Cargo.lock

@@ -17,7 +17,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "wasi-tests"
-version = "0.14.0"
+version = "0.15.0"
 dependencies = [
  "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "more-asserts 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",

crates/test-programs/wasi-tests/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "wasi-tests"
-version = "0.14.0"
+version = "0.15.0"
 authors = ["The Wasmtime Project Developers"]
 readme = "README.md"
 edition = "2018"