resolveName: remove useless case (microsoft#28669)

PropertySignature cannot occur in a class.
The condition inside the clause required the parent to be a class, so it was never true.

This removes the case clause and the part of the condition that is now useless.

Author: ajafff

src/compiler/checker.ts

@@ -1409,15 +1409,14 @@ namespace ts {
                         }
                         break;
                     case SyntaxKind.PropertyDeclaration:
-                    case SyntaxKind.PropertySignature:
                         // TypeScript 1.0 spec (April 2014): 8.4.1
                         // Initializer expressions for instance member variables are evaluated in the scope
                         // of the class constructor body but are not permitted to reference parameters or
                         // local variables of the constructor. This effectively means that entities from outer scopes
                         // by the same name as a constructor parameter or local variable are inaccessible
                         // in initializer expressions for instance member variables.
-                        if (isClassLike(location.parent) && !hasModifier(location, ModifierFlags.Static)) {
-                            const ctor = findConstructorDeclaration(location.parent);
+                        if (!hasModifier(location, ModifierFlags.Static)) {
+                            const ctor = findConstructorDeclaration(location.parent as ClassLikeDeclaration);
                             if (ctor && ctor.locals) {
                                 if (lookup(ctor.locals, name, meaning & SymbolFlags.Value)) {
                                     // Remember the property node, it will be used later to report appropriate error