Adjust receivers for possibly synthetic properties access

Synthetic property accessors are treated as extension functions on Java
classes by the front-end. However, underlying Java accessor methods are
proper members.

compiler/testData/ir/irText/stubs/javaSyntheticProperty.txt

@@ -3,7 +3,7 @@ FILE fqName:<root> fileName:/javaSyntheticProperty.kt
     FIELD PROPERTY_BACKING_FIELD name:test type:kotlin.String? visibility:public flags:final
       EXPRESSION_BODY
         CALL 'getFoo(): String!' type=kotlin.String? origin=GET_PROPERTY
-          $receiver: CALL 'constructor J()' type=J origin=null
+          $this: CALL 'constructor J()' type=J origin=null
     FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test> visibility:public modality:FINAL <> () returnType:kotlin.String? flags:
       correspondingProperty: PROPERTY name:test visibility:public modality:FINAL flags:val
       BLOCK_BODY

compiler/testData/ir/irText/stubs/jdkClassSyntheticProperty.txt

@@ -7,4 +7,4 @@ FILE fqName:<root> fileName:/jdkClassSyntheticProperty.kt
         RETURN type=kotlin.Nothing from='<get-test>() on Class<*>: Array<(out) Field!>!'
           CALL 'getDeclaredFields(): Array<(out) Field!>!' type=kotlin.Array<out java.lang.reflect.Field!>? origin=GET_PROPERTY
             <`0>: kotlin.Any?
-            $receiver: GET_VAR 'this@test: Class<*>' type=java.lang.Class<*> origin=null
+            $this: GET_VAR 'this@test: Class<*>' type=java.lang.Class<*> origin=null