[FIR] Add diagnostic CONFLICTING_PROJECTION

compiler/testData/diagnostics/tests/variance/InPosition.fir.kt

@@ -35,7 +35,7 @@ interface Test<in I, out O, P> {
     fun neOk6(i: In<In<O>>)
     fun neOk7(i: Pair<In<I>, O>)
     fun neOk8(i: Inv<out O>)
-    fun neOk9(i: In<out P>)
+    fun neOk9(i: <!CONFLICTING_PROJECTION!>In<out P><!>)
     fun neOk10(i: Out<O>)
 
     fun neOk11(i: Inv<in I>)

compiler/testData/diagnostics/tests/variance/InvariantPosition.fir.kt

@@ -23,7 +23,7 @@ interface Test<in I, out O, P> {
     var neOk7: Pair<In<I>, O>
     var neOk8: Inv<in O>
     var neOk9: Inv<in I>
-    var neOk10: In<out I>
+    var neOk10: <!CONFLICTING_PROJECTION!>In<out I><!>
 
     var neOk11: I
     var neOk12: In<O>

compiler/testData/diagnostics/tests/variance/OutPosition.fir.kt

@@ -28,7 +28,7 @@ interface Test<in I, out O, P> {
     fun neOk5(): Inv<O>
     fun neOk6(): Pair<In<O>, I>
     fun neOk7(): Inv<in O>
-    fun neOk8(): Out<in I>
+    fun neOk8(): <!CONFLICTING_PROJECTION!>Out<in I><!>
     
     fun neOk10(): Inv<in O>
     fun neOk11(): Inv<out I>