Merge wasmtime-jit and wasmtime-profiling (#3247)

* Merge `wasmtime-jit` and `wasmtime-profiling`

This commit merges the `wasmtime-profiling` crate into the
`wasmtime-jit` crate. It wasn't really buying a ton being a separate
crate and an upcoming refactoring I'd like to do is to remove the
`FinishedFunctions` structure. To enable the profilers to work as they
used to this commit changes them to pass `CompiledModule` as the
argument, but this only works if the profiling trait can see the
`CompiledModule` type.

* Fix a length calculation

crates/jit/src/profiling/jitdump_disabled.rs

@@ -0,0 +1,23 @@
+use crate::{CompiledModule, ProfilingAgent};
+use anyhow::{bail, Result};
+
+/// Interface for driving the creation of jitdump files
+#[derive(Debug)]
+pub struct JitDumpAgent {
+    _private: (),
+}
+
+impl JitDumpAgent {
+    /// Intialize a JitDumpAgent and write out the header
+    pub fn new() -> Result<Self> {
+        if cfg!(feature = "jitdump") {
+            bail!("jitdump is not supported on this platform");
+        } else {
+            bail!("jitdump support disabled at compile time");
+        }
+    }
+}
+
+impl ProfilingAgent for JitDumpAgent {
+    fn module_load(&self, _module: &CompiledModule, _dbg_image: Option<&[u8]>) {}
+}