Detect unused files in src/test/mir-opt and error on them in tidy.

Author: JakobDegen

Cargo.lock

@@ -816,6 +816,7 @@ dependencies = [
  "lazycell",
  "libc",
  "miow",
+ "miropt-test-tools",
  "regex",
  "rustfix",
  "serde",
@@ -2268,6 +2269,13 @@ dependencies = [
  "ui_test",
 ]
 
+[[package]]
+name = "miropt-test-tools"
+version = "0.1.0"
+dependencies = [
+ "regex",
+]
+
 [[package]]
 name = "new_debug_unreachable"
 version = "1.0.4"
@@ -4920,6 +4928,7 @@ version = "0.1.0"
 dependencies = [
  "cargo_metadata 0.14.0",
  "lazy_static",
+ "miropt-test-tools",
  "regex",
  "walkdir",
 ]

Cargo.toml

@@ -11,6 +11,7 @@ members = [
   "src/tools/error_index_generator",
   "src/tools/linkchecker",
   "src/tools/lint-docs",
+  "src/tools/miropt-test-tools",
   "src/tools/rustbook",
   "src/tools/unstable-book-gen",
   "src/tools/tidy",

src/bootstrap/builder.rs

@@ -622,6 +622,7 @@ impl<'a> Builder<'a> {
                 check::Clippy,
                 check::Miri,
                 check::CargoMiri,
+                check::MiroptTestTools,
                 check::Rls,
                 check::RustAnalyzer,
                 check::Rustfmt,

src/bootstrap/check.rs

@@ -460,6 +460,7 @@ tool_check_step!(Miri, "src/tools/miri", SourceType::InTree);
 tool_check_step!(CargoMiri, "src/tools/miri/cargo-miri", SourceType::InTree);
 tool_check_step!(Rls, "src/tools/rls", SourceType::InTree);
 tool_check_step!(Rustfmt, "src/tools/rustfmt", SourceType::InTree);
+tool_check_step!(MiroptTestTools, "src/tools/miropt-test-tools", SourceType::InTree);
 
 tool_check_step!(Bootstrap, "src/bootstrap", SourceType::InTree, false);