FIR: use dispatch receiver of the enclosing function if any.

compiler/testData/codegen/box/defaultArguments/protected.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // FILE: Foo.kt
 
 package foo

compiler/testData/codegen/box/defaultArguments/useThisInLambda.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 class X {
     fun g(x: () -> Boolean = { super.equals(this) }) = x()
 }