[NI] Avoid constraints from expected type for effectively empty system

Expression will be checked against expected type later.

 Theoretically, this is not very good, but it aligns with the old
 inference, plus it helps avoiding multiple type mismatch diagnostics.

compiler/testData/diagnostics/tests/annotations/kt1860-negative.kt

@@ -4,7 +4,7 @@ fun foo(@<!UNRESOLVED_REFERENCE!>varargs<!> <!UNUSED_PARAMETER!>f<!> : Int) {}
 var bar : Int = 1
   set(@<!UNRESOLVED_REFERENCE!>varargs<!> <!UNUSED_PARAMETER!>v<!>) {}
 
-val x : (Int) -> Int = {@<!UNRESOLVED_REFERENCE!>varargs<!> <!NI;TYPE_MISMATCH, TYPE_MISMATCH, UNINITIALIZED_VARIABLE!>x<!> <!SYNTAX!>: Int -> x<!>}
+val x : (Int) -> Int = {@<!UNRESOLVED_REFERENCE!>varargs<!> <!TYPE_MISMATCH, UNINITIALIZED_VARIABLE!>x<!> <!SYNTAX!>: Int -> x<!>}
 
 class Hello(@<!UNRESOLVED_REFERENCE!>varargs<!> <!UNUSED_PARAMETER!>args<!>: Any) {
 }

compiler/testData/diagnostics/tests/annotations/kt1860-positive.kt

@@ -8,7 +8,7 @@ fun foo(@test <!UNUSED_PARAMETER!>f<!> : Int) {}
 var bar : Int = 1
     set(@test <!UNUSED_PARAMETER!>v<!>) {}
 
-val x : (Int) -> Int = {@test <!NI;TYPE_MISMATCH, TYPE_MISMATCH, UNINITIALIZED_VARIABLE!>x<!> <!SYNTAX!>: Int -> x<!>} // todo fix parser annotation on lambda parameter
+val x : (Int) -> Int = {@test <!TYPE_MISMATCH, UNINITIALIZED_VARIABLE!>x<!> <!SYNTAX!>: Int -> x<!>} // todo fix parser annotation on lambda parameter
 
 class Hello(@test <!UNUSED_PARAMETER!>args<!>: Any) {
 }