[FIR] Resolve infix calls to infix functions only

Implements INFIX_MODIFIER_REQUIRED diagnostics

compiler/testData/diagnostics/tests/modifiers/operatorInfix/LocalFunctions.fir.kt

@@ -24,13 +24,13 @@ fun a() {
             consumeInt(<!ARGUMENT_TYPE_MISMATCH!>a - b<!>)
 
             consumeString(a plus b)
-            consumeInt(<!ARGUMENT_TYPE_MISMATCH!>a minus b<!>)
+            consumeInt(a minus b)
 
             a * b
             a / b
 
             a times b
-            a div b
+            a <!INFIX_MODIFIER_REQUIRED!>div<!> b
         }
     }
 }

compiler/testData/diagnostics/tests/modifiers/operatorInfix/MemberFunctions.fir.kt

@@ -26,7 +26,7 @@ fun a() {
     a plus b
     a minus b
     a times b
-    a div b
+    a <!INFIX_MODIFIER_REQUIRED!>div<!> b
 
     with (Example()) {
         consumeInt(this + a)
@@ -35,9 +35,9 @@ fun a() {
         consumeInt(this / b)
 
         consumeInt(this plus a)
-        consumeString(<!ARGUMENT_TYPE_MISMATCH!>this minus b<!>)
+        consumeString(this minus b)
         consumeInt(this times a)
-        consumeInt(this div b)
+        consumeInt(this <!INFIX_MODIFIER_REQUIRED!>div<!> b)
     }
 }
 

compiler/testData/diagnostics/tests/modifiers/operatorInfix/Simple.fir.kt

@@ -37,7 +37,7 @@ fun test() {
 
     consumeExample2(<!ARGUMENT_TYPE_MISMATCH!>++a<!>)
 
-    consumeString(<!ARGUMENT_TYPE_MISMATCH!>a plus b<!>)
+    consumeString(a plus b)
 }
 
 fun consumeInt(i: Int) {}