[JS][Tests] Unify setup of loweredIrHandlersStep

^KT-72594

js/js.tests/testFixtures/org/jetbrains/kotlin/js/test/fir/AbstractFirPsiJsDiagnosticTest.kt

diff --git a/js/js.tests/testFixtures/org/jetbrains/kotlin/js/test/fir/AbstractFirPsiJsDiagnosticTest.kt b/js/js.tests/testFixtures/org/jetbrains/kotlin/js/test/fir/AbstractFirPsiJsDiagnosticTest.kt
index 409eab9..04a0b9f 100644
--- a/js/js.tests/testFixtures/org/jetbrains/kotlin/js/test/fir/AbstractFirPsiJsDiagnosticTest.kt
+++ b/js/js.tests/testFixtures/org/jetbrains/kotlin/js/test/fir/AbstractFirPsiJsDiagnosticTest.kt
@@ -58,6 +58,9 @@
         configureIrHandlersStep {
             useHandlers(::IrDiagnosticsHandler)
         }
+        configureLoweredIrHandlersStep {
+            useHandlers(::IrDiagnosticsHandler)
+        }
 
         useAfterAnalysisCheckers(
             ::PhasedPipelineChecker.bind(TestPhase.FRONTEND),
@@ -81,11 +84,6 @@
 abstract class AbstractFirJsDiagnosticWithBackendTestBase(parser: FirParser) : AbstractFirJsDiagnosticTestBase(parser) {
     override fun configure(builder: TestConfigurationBuilder) = with(builder) {
         super.configure(builder)
-        configureLoweredIrHandlersStep {
-            useHandlers(
-                ::IrDiagnosticsHandler
-            )
-        }
         klibArtifactsHandlersStep {
             useHandlers(::KlibBackendDiagnosticsHandler)
         }
@@ -116,12 +114,6 @@
                 "+${LanguageFeature.IrCrossModuleInlinerBeforeKlibSerialization.name}"
             )
         }
-
-        configureLoweredIrHandlersStep {
-            useHandlers(
-                ::IrDiagnosticsHandler
-            )
-        }
     }
 }