[FIR] Add a minimized alternative for orOperatorWithConstant.kt

It was decided to leave this code as is, because supporting
it would probably require introducing Implication-statements,
but this is not a good-enough use-case for such work.

compiler/testData/diagnostics/tests/smartCasts/smartCastWithOrFalse.kt

@@ -0,0 +1,8 @@
+fun main(x: Any?) {
+    if (x is String || false) {
+        <!DEBUG_INFO_SMARTCAST!>x<!>.length
+    }
+    else {
+        x.<!UNRESOLVED_REFERENCE!>length<!>
+    }
+}