fixup: remove mutex from pass manager

Author: abulavin

mlir/include/mlir/Pass/PassManager.h

@@ -17,7 +17,6 @@
 #include "llvm/Support/raw_ostream.h"
 
 #include <functional>
-#include <mutex>
 #include <optional>
 
 namespace mlir {
@@ -498,10 +497,6 @@ class PassManager : public OpPassManager {
 
   /// A flag that indicates if the IR should be verified in between passes.
   bool verifyPasses : 1;
-
-  /// A mutex used to serialixe thread access when running the pass manager with
-  /// crash reproduction enabled.
-  std::mutex crashRecoveryLock;
 };
 
 /// Register a set of useful command-line options that can be used to configure