Reset SynchronizedBlock cache after each iteration

Source/Test/Rewriting/Types/Threading/Monitor.cs

@@ -429,6 +429,13 @@ private SynchronizedBlock(CoyoteRuntime runtime, object syncObject)
                 this.DebugName = $"lock({this.ResourceId})";
             }
 
+            /// <summary>
+            /// Called to clear out the cache of synchronized blocks in cases where an iteration
+            /// may have been aborted and the cache is no longer valid, and may even hold old
+            /// values that would otherwise not get cleaned up and could impact future iterations.
+            /// </summary>
+            internal static void ResetCache () => Cache.Clear();
+
             /// <summary>
             /// Creates a new <see cref="SynchronizedBlock"/> for synchronizing access
             /// to the specified object and enters the lock.

Source/Test/SystematicTesting/TestingEngine.cs

@@ -21,6 +21,8 @@
 using Microsoft.Coyote.Telemetry;
 using Microsoft.Coyote.Visualization;
 
+using SynchronizedBlock = Microsoft.Coyote.Rewriting.Types.Threading.Monitor.SynchronizedBlock;
+
 namespace Microsoft.Coyote.SystematicTesting
 {
     /// <summary>
@@ -201,6 +203,9 @@ private TestingEngine(Configuration configuration, TestMethodInfo testMethodInfo
 
             // Create a client for gathering and sending optional telemetry data.
             TelemetryClient = TelemetryClient.GetOrCreate(this.Configuration, this.LogWriter);
+
+            // Register to clean up the Monitor SynchronizedBlock cache.
+            this.RegisterEndIterationCallBack(_ => SynchronizedBlock.ResetCache());
         }
 
         /// <summary>