Update signatures to avoid post-LKG error (microsoft#48677)

Author: andrewbranch

src/deprecatedCompat/deprecations.ts

@@ -1125,7 +1125,7 @@ namespace ts {
         name: PropertyName | string,
         questionToken: QuestionToken | undefined,
         type: TypeNode | undefined,
-        initializer?: Expression
+        initializer?: Expression | undefined
     ): PropertySignature {
         const node = factory.createPropertySignature(modifiers, name, questionToken, type);
         node.initializer = initializer;
@@ -1187,7 +1187,7 @@ namespace ts {
             arguments.length >= 1 && arguments.length <= 3 ? factory.createVariableDeclaration(name, /*exclamationToken*/ undefined, exclamationTokenOrType as TypeNode | undefined, typeOrInitializer as Expression | undefined) :
             Debug.fail("Argument count mismatch");
     } as {
-        (name: string | BindingName, type?: TypeNode, initializer?: Expression): VariableDeclaration;
+        (name: string | BindingName, type?: TypeNode | undefined, initializer?: Expression | undefined): VariableDeclaration;
         (name: string | BindingName, exclamationToken: ExclamationToken | undefined, type: TypeNode | undefined, initializer: Expression | undefined): VariableDeclaration;
     }, factoryDeprecation);
 
@@ -1212,7 +1212,7 @@ namespace ts {
     }, factoryDeprecation);
 
     /** @deprecated Use `factory.createExportDeclaration` or the factory supplied by your transformation context instead. */
-    export const createExportDeclaration = Debug.deprecate(function createExportDeclaration(decorators: readonly Decorator[] | undefined, modifiers: readonly Modifier[] | undefined, exportClause: NamedExportBindings | undefined, moduleSpecifier?: Expression, isTypeOnly = false) {
+    export const createExportDeclaration = Debug.deprecate(function createExportDeclaration(decorators: readonly Decorator[] | undefined, modifiers: readonly Modifier[] | undefined, exportClause: NamedExportBindings | undefined, moduleSpecifier?: Expression | undefined, isTypeOnly = false) {
         return factory.createExportDeclaration(decorators, modifiers, isTypeOnly, exportClause, moduleSpecifier);
     }, factoryDeprecation);
 
@@ -1228,7 +1228,7 @@ namespace ts {
     }, factoryDeprecation);
 
     /** @deprecated Use `factory.createJSDocParameterTag` or the factory supplied by your transformation context instead. */
-    export const createJSDocParamTag = Debug.deprecate(function createJSDocParamTag(name: EntityName, isBracketed: boolean, typeExpression?: JSDocTypeExpression, comment?: string): JSDocParameterTag {
+    export const createJSDocParamTag = Debug.deprecate(function createJSDocParamTag(name: EntityName, isBracketed: boolean, typeExpression?: JSDocTypeExpression | undefined, comment?: string | undefined): JSDocParameterTag {
         return factory.createJSDocParameterTag(/*tagName*/ undefined, name, isBracketed, typeExpression, /*isNameFirst*/ false, comment ? factory.createNodeArray([factory.createJSDocText(comment)]) : undefined);
     }, factoryDeprecation);