Place VM reset in Runtime Core mutex context (#10577)

Enlarged the mutually exclusive context in ResetVMAndResyncGraph to
also include ReInitializeLiveRunner. This is important as the
reinitialization of the runner resets the runtime core, making the
Design Script executable null, which will cause any running executions
to crash Dynamo, even respecting the mutually exclusive context.

src/Engine/ProtoScript/Runners/LiveRunner.cs

@@ -1278,6 +1278,7 @@ public void UpdateGraph(AssociativeNode astNode)
         /// This api needs to be called by a command line REPL for each DS command/expression entered to be executed
         /// </summary>
         /// <param name="code"></param>
+        [Obsolete("No longer used. Remove in 3.0")]
         public void UpdateCmdLineInterpreter(string code)
         {
             lock (mutexObject)
@@ -1532,27 +1533,30 @@ public void ReInitializeLiveRunner()
         /// <param name="syncData"></param>
         public void ResetVMAndResyncGraph(IEnumerable<string> libraries)
         {
-            // Reset VM
-            ReInitializeLiveRunner();
-
-            if (!libraries.Any())
+            lock (mutexObject)
             {
-                return;
-            }
+                // Reset VM. This needs to be in mutex context as it turns DSExecutable null.
+                ReInitializeLiveRunner();
 
-            // generate import node for each library in input list
-            List<AssociativeNode> importNodes = new List<AssociativeNode>();
-            foreach (string lib in libraries)
-            {
-                ProtoCore.AST.AssociativeAST.ImportNode importNode = new ProtoCore.AST.AssociativeAST.ImportNode();
-                importNode.ModuleName = lib;
+                if (!libraries.Any())
+                {
+                    return;
+                }
 
-                importNodes.Add(importNode);
-            }
-            ProtoCore.CodeGenDS codeGen = new ProtoCore.CodeGenDS(importNodes);
-            string code = codeGen.GenerateCode();
+                // generate import node for each library in input list
+                List<AssociativeNode> importNodes = new List<AssociativeNode>();
+                foreach (string lib in libraries)
+                {
+                    ProtoCore.AST.AssociativeAST.ImportNode importNode = new ProtoCore.AST.AssociativeAST.ImportNode();
+                    importNode.ModuleName = lib;
 
-            UpdateCmdLineInterpreter(code);
+                    importNodes.Add(importNode);
+                }
+                ProtoCore.CodeGenDS codeGen = new ProtoCore.CodeGenDS(importNodes);
+                string code = codeGen.GenerateCode();
+
+                SynchronizeInternal(code);
+            }
         }
 
         /// <summary>