Revert #3539 and reuse rust backend infrastructure instead (#3545)

Replace the body by a call to link_binary as other backend
implementations do, e.g.
[rustc_codegen_gcc](https://github.com/rust-lang/rust/blob/648d024a7859e1ab7fdffe5e419b6e35ccb16a4a/compiler/rustc_codegen_gcc/src/lib.rs#L269-L271).
Also remove the implementation of `metadata_loader` which has a [default
body](https://github.com/rust-lang/rust/blob/11e760b7f4e4aaa11bf51a64d4bb7f1171f6e466/compiler/rustc_codegen_ssa/src/traits/backend.rs#L58-L60).

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 and MIT licenses.

---------

Co-authored-by: Michael Tautschnig <tautschn@amazon.com>

Cargo.lock

@@ -248,15 +248,6 @@ dependencies = [
  "tracing",
 ]
 
-[[package]]
-name = "crc32fast"
-version = "1.4.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a97769d94ddab943e4510d138150169a2758b5ef3eb191a9ee688de3e23ef7b3"
-dependencies = [
- "cfg-if",
-]
-
 [[package]]
 name = "crossbeam-deque"
 version = "0.8.5"
@@ -485,7 +476,6 @@ dependencies = [
  "kani_metadata",
  "lazy_static",
  "num",
- "object",
  "quote",
  "regex",
  "serde",
@@ -728,19 +718,6 @@ dependencies = [
  "autocfg",
 ]
 
-[[package]]
-name = "object"
-version = "0.36.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "084f1a5821ac4c651660a94a7153d27ac9d8a53736203f58b31945ded098070a"
-dependencies = [
- "crc32fast",
- "hashbrown",
- "indexmap",
- "memchr",
- "wasmparser",
-]
-
 [[package]]
 name = "once_cell"
 version = "1.19.0"
@@ -1427,15 +1404,6 @@ version = "0.11.0+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
 
-[[package]]
-name = "wasmparser"
-version = "0.216.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bcdee6bea3619d311fb4b299721e89a986c3470f804b6d534340e412589028e3"
-dependencies = [
- "bitflags",
-]
-
 [[package]]
 name = "which"
 version = "6.0.3"

kani-compiler/Cargo.toml

@@ -28,11 +28,6 @@ tracing = {version = "0.1", features = ["max_level_trace", "release_max_level_de
 tracing-subscriber = {version = "0.3.8", features = ["env-filter", "json", "fmt"]}
 tracing-tree = "0.4.0"
 
-[dependencies.object]
-version = "0.36.2"
-default-features = false
-features = ["elf", "macho", "pe", "xcoff", "write", "wasm"]
-
 # Future proofing: enable backend dependencies using feature.
 [features]
 default = ['cprover']