FIR2IR: Fix complex cases of smart cast expressions used as dispatch receiver

It might be not only <ExpressionWithSmartCast>(a).foo(), but also
id(<ExpressionWithSmartCast>(a)).foo() and many other cases

compiler/testData/ir/irText/expressions/dotQualified.kt.txt

@@ -7,8 +7,7 @@ fun lengthN(s: String?): Int? {
     val tmp0_safe_receiver: String? = s
     when {
       EQEQ(arg0 = tmp0_safe_receiver, arg1 = null) -> null
-      else -> tmp0_safe_receiver.<get-length>()
+      else -> tmp0_safe_receiver /*as String */.<get-length>()
     }
   }
 }
-