[FIR] Fix tests (ARGUMENT_TYPE_MISMATCH instead of INCOMPATIBLE_CANDIDATE)

compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/kt2216.fir.kt

@@ -15,8 +15,8 @@ fun foo() {
 
     val y: Int? = 0
     val z: Int? = 0
-    <!INAPPLICABLE_CANDIDATE!>bar<!>(if (y != null) y else z, y)
+    bar(<!ARGUMENT_TYPE_MISMATCH!>if (y != null) y else z<!>, <!ARGUMENT_TYPE_MISMATCH!>y<!>)
     y <!NONE_APPLICABLE!>+<!> 2
-    <!INAPPLICABLE_CANDIDATE!>baz<!>(y, y, if (y == null) return else y, y)
+    baz(<!ARGUMENT_TYPE_MISMATCH!>y<!>, <!ARGUMENT_TYPE_MISMATCH!>y<!>, if (y == null) return else y, y)
     baz(y, z!!, z, y)
 }