Fix testing wiggle and wiggle-test in isolation (#12286)

* Migrate wiggle and wiggle generate to `wasmtime::error`

* Fix testing `wiggle` and `wiggle-test` in isolation

When doing plain old `cargo test -p wiggle` (or `wiggle-test`) the test would
fail due to linking errors because Wasmtime's `std` cargo feature (and maybe
others) wasn't being enabled. The crate's tests would pass when run as part of
the whole workspace, however, because of cargo feature resolution and other
crates that enabled the necessary features, which is why CI is green.

Author: fitzgen

Cargo.lock

@@ -27,7 +27,10 @@ wasmtime-environ = { workspace = true }
 wiggle-test = { path = "test-helpers" }
 proptest = "1.0.0"
 tokio = { version = "1", features = ["rt-multi-thread","time", "macros"] }
-wasmtime = { workspace = true }
+# Explicitly enable default features so that tests pass even testing only this
+# crate in isolation and we can't accidentally rely on cargo feature resolution
+# to enable the runtime and compiler.
+wasmtime = { workspace = true, features = ["default"] }
 
 [[test]]
 name = "atoms_async"

crates/wiggle/Cargo.toml

@@ -25,3 +25,7 @@ thiserror = { workspace = true }
 tracing = { workspace = true }
 tracing-subscriber = { version = "0.3.1", default-features = false, features = ['fmt'] }
 env_logger = { workspace = true }
+# Explicitly enable default features so that tests pass even testing only this
+# crate in isolation and we can't accidentally rely on cargo feature resolution
+# to enable the runtime and compiler.
+wasmtime = { workspace = true, features = ["default"] }