mark wrapper methods that pass default values of parameters as synthetic

#KT-7314 Fixed

compiler/testData/codegen/boxWithStdlib/defaultArguments/constructor/checkIfConstructorIsSynthetic.kt

@@ -0,0 +1,6 @@
+class A(value: Int = 1)
+
+fun box(): String {
+    val constructors = javaClass<A>().getConstructors().filter { !it.isSynthetic() }
+    return if (constructors.size() == 2) "OK" else constructors.size().toString()
+}