Add declaration emit tests for readonly parameter property

tests/baselines/reference/declarationEmit_readonly.js

@@ -0,0 +1,20 @@
+//// [declarationEmit_readonly.ts]
+
+class C {
+    constructor(readonly x: number) {}
+}
+
+//// [declarationEmit_readonly.js]
+var C = (function () {
+    function C(x) {
+        this.x = x;
+    }
+    return C;
+}());
+
+
+//// [declarationEmit_readonly.d.ts]
+declare class C {
+    readonly x: number;
+    constructor(x: number);
+}

tests/baselines/reference/declarationEmit_readonly.symbols

@@ -0,0 +1,8 @@
+=== tests/cases/conformance/classes/constructorDeclarations/constructorParameters/declarationEmit_readonly.ts ===
+
+class C {
+>C : Symbol(C, Decl(declarationEmit_readonly.ts, 0, 0))
+
+    constructor(readonly x: number) {}
+>x : Symbol(C.x, Decl(declarationEmit_readonly.ts, 2, 16))
+}

tests/baselines/reference/declarationEmit_readonly.types

@@ -0,0 +1,8 @@
+=== tests/cases/conformance/classes/constructorDeclarations/constructorParameters/declarationEmit_readonly.ts ===
+
+class C {
+>C : C
+
+    constructor(readonly x: number) {}
+>x : number
+}

tests/cases/conformance/classes/constructorDeclarations/constructorParameters/declarationEmit_readonly.ts

@@ -0,0 +1,5 @@
+// @declaration: true
+
+class C {
+    constructor(readonly x: number) {}
+}