winch: Adding support for integration tests (#5588)

* Adding in the foundations for Winch `filetests`

This commit adds two new crates into the Winch workspace:
`filetests` and `test-macros`. The intent is to mimic the
structure of Cranelift `filetests`, but in a simpler way.

* Updates to documentation

This commits adds a high level document to outline how to test Winch
through the `winch-tools` utility. It also updates some inline
documentation which gets propagated to the CLI.

* Updating test-macro to use a glob instead of only a flat directory

winch/Cargo.toml

@@ -11,9 +11,10 @@ edition.workspace = true
 name = "winch-tools"
 path = "src/main.rs"
 
-
 [dependencies]
 winch-codegen = { workspace = true }
+winch-filetests = { workspace = true }
+winch-test-macros = { workspace = true }
 wasmtime-environ = { workspace = true }
 target-lexicon = { workspace = true }
 anyhow = { workspace = true }
@@ -22,6 +23,10 @@ clap = { workspace = true }
 wat = { workspace = true }
 cranelift-codegen = { workspace = true }
 capstone = { workspace = true }
+similar = { workspace = true }
+toml = { workspace = true }
+serde = { workspace = true }
+glob = { workspace = true }
 
 [features]
 default = ["all-arch"]