Regular modifier checker implemented (initial version). A set of tests fixed accordingly.

Most of modifier diagnostic is expressed by REDUNDANT_MODIFIER, INCOMPATIBLE_MODIFIERS, REPEATED_MODIFIER, WRONG_MODIFIER_TARGET, WRONG_MODIFIER_PARENT.
A set of modifier diagnostics is not in use now (but not deleted yet).

compiler/testData/diagnostics/tests/delegation/DelegationNotTotrait.kt

@@ -8,7 +8,7 @@ interface T {}
 
 class Br(t : T) : T by t {}
 
-<!OPEN_MODIFIER_IN_ENUM!>open<!> enum class EN() {
+<!WRONG_MODIFIER_TARGET!>open<!> enum class EN() {
   A
 }