Currently FirThisReceiverExpression of instance methods are translated
to references of the class' thisReceiver,
not the method's dispatch receiver,
which causes problems with IrFrameMap::typeOf,
as the class' thisReceiver is not in the typeMap.
This commit translates non-qualified "this" references of
instance methods to references of the methods' dispatch receiver.
Quoted from https://kotlinlang.org/docs/reference/classes.html
"On the JVM, if all of the parameters of the primary constructor have
default values, the compiler will generate an additional parameterless
constructor which will use the default values. This makes it easier to
use Kotlin with libraries such as Jackson or JPA that create class
instances through parameterless constructors."
Juan Chen