[FE] Drop ApproximateIntegerLiteralTypesInReceiverPosition language feature

This feature is not needed because it is unconditionally disabled for K1
  (because of not fully correct implementation) and unconditionally enabled
  in K2 (K2 does not support old behavior)

^KT-38895

compiler/testData/codegen/box/binaryOp/callNullable.kt

@@ -1,6 +1,5 @@
-// LANGUAGE: -ApproximateIntegerLiteralTypesInReceiverPosition
 // IGNORE_BACKEND_K2: JVM_IR, JS_IR
-// FIR status: don't support legacy feature; for reasons this test is ignored, go to KT-46419
+// FIR status: KT-46419, ILT conversions to Byte and Short are not supported by design
 
 fun box(): String {
     val a1: Byte? = 1.plus(1)