K2: Get rid of last unhandled CheckerContext modification

Previously, it was necessary because otherwise reporting diagnostics
from a checker of FirFile level didn't work

Now, it has been fixed in the previous commit

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirConflictsChecker.kt

@@ -232,8 +232,6 @@ object FirConflictsChecker : FirBasicDeclarationChecker() {
             }
         }
 
-        context.addDeclaration(declaration)
-        try {
         inspector.declarationConflictingSymbols.forEach { (conflictingDeclaration, symbols) ->
             val source = conflictingDeclaration.source
             if (source != null && symbols.isNotEmpty()) {
@@ -272,9 +270,6 @@ object FirConflictsChecker : FirBasicDeclarationChecker() {
                 }
             }
         }
-        } finally {
-            context.dropDeclaration()
-        }
     }
 
     private fun checkConflictingParameters(parameters: List<FirElement>, context: CheckerContext, reporter: DiagnosticReporter) {
@@ -381,5 +376,3 @@ private fun FirRegularClass.onConstructors(action: (ctor: FirConstructor) -> Uni
         acceptChildren(ClassConstructorVisitor())
     }
 }
-
-