Reduce polymorphism resulting from unstable Node shapes (#51682)

* Move .symbol to Declaration

* simplify some factories

* Move localSymbol to Declaration

* Ensure JSDocContainer types are properly initialized

* Move contextualType from Node to NodeLinks

* Move 'locals' and 'nextContainer' out of Node

* Move 'flowNode' out of 'Node'

* Pre-define endFlowNode/returnFlowNode

* Pre-define some SourceFile properties and a more stable cloneNode

* Don't add excess properties to type nodes in typeToTypeNode

* Refactor wrapSymbolTrackerToReportForContext to improve perf

src/services/documentHighlights.ts

@@ -5,6 +5,7 @@ import {
     Block,
     BreakOrContinueStatement,
     CancellationToken,
+    canHaveSymbol,
     CaseClause,
     cast,
     concatenate,
@@ -78,6 +79,7 @@ import {
     ThrowStatement,
     toArray,
     toPath,
+    tryCast,
     TryStatement,
 } from "./_namespaces/ts";
 
@@ -184,7 +186,7 @@ export namespace DocumentHighlights {
         }
 
         function getFromAllDeclarations<T extends Node>(nodeTest: (node: Node) => node is T, keywords: readonly SyntaxKind[]): HighlightSpan[] | undefined {
-            return useParent(node.parent, nodeTest, decl => mapDefined(decl.symbol.declarations, d =>
+            return useParent(node.parent, nodeTest, decl => mapDefined(tryCast(decl, canHaveSymbol)?.symbol.declarations, d =>
                 nodeTest(d) ? find(d.getChildren(sourceFile), c => contains(keywords, c.kind)) : undefined));
         }