Fix implement interface codefix for synthetic member symbols (#35718)

Author: andrewbranch

src/services/codefixes/fixClassIncorrectlyImplementsInterface.ts

@@ -34,7 +34,7 @@ namespace ts.codefix {
     }
 
     function symbolPointsToNonPrivateMember (symbol: Symbol) {
-        return !(getModifierFlags(symbol.valueDeclaration) & ModifierFlags.Private);
+        return !symbol.valueDeclaration || !(getModifierFlags(symbol.valueDeclaration) & ModifierFlags.Private);
     }
 
     function addMissingDeclarations(

tests/cases/fourslash/codefixClassImplementInterface_omit.ts

@@ -0,0 +1,30 @@
+/// <reference path="fourslash.ts" />
+
+////interface One {
+////    a: number;
+////    b: string;
+////}
+////
+////interface Two extends Omit<One, "a"> {
+////    c: boolean;
+////}
+////
+////class TwoStore implements Two {[| |]}
+
+verify.codeFix({
+  description: "Implement interface 'Two'",
+  newFileContent:
+`interface One {
+    a: number;
+    b: string;
+}
+
+interface Two extends Omit<One, "a"> {
+    c: boolean;
+}
+
+class TwoStore implements Two {
+    c: boolean;
+    b: string;
+}`,
+});