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/safeAssignment.fir.kt.txt

@@ -17,7 +17,7 @@ fun test(nc: C?) {
     val tmp0_safe_receiver: C? = nc
     when {
       EQEQ(arg0 = tmp0_safe_receiver, arg1 = null) -> null
-      else -> tmp0_safe_receiver.<set-x>(<set-?> = 42)
+      else -> tmp0_safe_receiver /*as C */.<set-x>(<set-?> = 42)
     }
   } /*~> Unit */
 }