[FIR] Resolve infix calls to infix functions only

Implements INFIX_MODIFIER_REQUIRED diagnostics

compiler/resolution.common/src/org/jetbrains/kotlin/resolve/calls/tower/CandidateApplicability.kt

@@ -11,6 +11,7 @@ enum class CandidateApplicability {
     INAPPLICABLE_WRONG_RECEIVER, // receiver not matched
     INAPPLICABLE_ARGUMENTS_MAPPING_ERROR, // arguments not mapped to parameters (i.e. different size of arguments and parameters)
     INAPPLICABLE, // arguments have wrong types
+    INAPPLICABLE_MODIFIER, // no expected modifier (eg infix call on non-infix function)
     IMPOSSIBLE_TO_GENERATE, // access to outer class from nested
     RUNTIME_ERROR, // problems with visibility
     UNSAFE_CALL, // receiver nullability doesn't match