KT-52373 Fix generation of synthetic functions with context receivers and default parameters

compiler/testData/codegen/box/extensionFunctions/contextReceivers/kt52373.kt

@@ -0,0 +1,18 @@
+// !LANGUAGE: +ContextReceivers
+// TARGET_BACKEND: JVM_IR
+
+class Context
+class Extended
+
+class Containing {
+    context(Context) fun Extended.foo(obj: Any? = null) {}
+}
+
+fun box(): String {
+    with (Containing()) {
+        with (Context()) {
+            Extended().foo()
+        }
+    }
+    return "OK"
+}