[FIR] Move registration components out of initializers of FirSession

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/CheckersComponent.kt

@@ -43,6 +43,14 @@ class CheckersComponent : FirSessionComponent {
 
 val FirSession.checkersComponent: CheckersComponent by FirSession.sessionComponentAccessor()
 
+/*
+ * TODO: in future rename to `registerCheckersComponent` and configure
+ *    exact checkers according to platforms of current session
+ */
+fun FirSession.registerCheckersComponent() {
+    register(CheckersComponent::class, CheckersComponent.componentWithDefaultCheckers())
+}
+
 private class ComposedDeclarationCheckers : DeclarationCheckers() {
     override val declarationCheckers: List<FirBasicDeclarationChecker>
         get() = _declarationCheckers