[NI] Turn off KnownTypeParameterSubstitutor for NI

The main consequence of it is that TYPE_MISMATCH range for control
structures became wider.

Also, for extra safety, don't change behaviour of OI.

compiler/testData/diagnostics/tests/smartCasts/variables/ifNullAssignment.kt

@@ -3,7 +3,7 @@
 
 fun basic(): String {
     var current: String? = null
-    current = if (current == null) "bar" else current
+    current = if (current == null) "bar" else <!NI;DEBUG_INFO_SMARTCAST!>current<!>
     return <!DEBUG_INFO_SMARTCAST!>current<!>
 }