Extract jit_int.rs and most of jitdump_linux.rs for use outside of wasmtime (#2744)

* Extract gdb jit_int into wasmtime-jit-debug

* Move a big chunk of the jitdump code to wasmtime-jit-debug

* Fix doc markdown in perf_jitdump.rs

crates/jit-debug/Cargo.toml

@@ -0,0 +1,25 @@
+[package]
+name = "wasmtime-jit-debug"
+version = "0.34.0"
+authors = ["The Wasmtime Project Developers"]
+description = "JIT debug interfaces support for Wasmtime"
+license = "Apache-2.0 WITH LLVM-exception"
+categories = ["development-tools::debugging"]
+keywords = ["gdb", "jit"]
+repository = "https://github.com/bytecodealliance/wasmtime"
+readme = "README.md"
+edition = "2018"
+
+[dependencies]
+lazy_static = {version = "1.3.0", optional = true }
+object = { version = "0.27.0", default-features = false, features = ["std", "read_core"], optional = true }
+
+[target.'cfg(target_os = "linux")'.dependencies]
+rustix = { version = "0.33.0", optional = true }
+
+[badges]
+maintenance = { status = "actively-developed" }
+
+[features]
+gdb_jit_int = ["lazy_static"]
+perf_jitdump = ["rustix", "object"]