chore: refactor ensureConstructor with CommonNames instead of raw string (#2935)

Author: HerrCai0907

src/compiler.ts

@@ -8830,7 +8830,7 @@ export class Compiler extends DiagnosticEmitter {
  classInstance.constructorInstance = instance;
  let members = classInstance.members;
  if (!members) classInstance.members = members = new Map();
- members.set("constructor", instance.prototype);
+ members.set(CommonNames.constructor, instance.prototype);
 
  let previousFlow = this.currentFlow;
  let flow = instance.flow;