default -> companion: replace all mentions of default and default object

compiler/testData/codegen/box/defaultArguments/function/extentionFunctionInClassObject.kt

@@ -1,5 +1,5 @@
 class A {
-  default object {
+  companion object {
     fun Int.foo(a: Int = 1): Int {
         return a
     }

compiler/testData/codegen/box/defaultArguments/function/mixingNamedAndPositioned.kt

@@ -1,4 +1,4 @@
-fun foo(a: String = "Default", b: Int = 1, c: Long = 2): String {
+fun foo(a: String = "Companion", b: Int = 1, c: Long = 2): String {
   return "$a $b $c"
 }