[LL FIR] mark LLFirTargetResolver and LLFirLazyResolver as sealed as we know hierarchy

analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/transformers/LLFirAbstractBodyTargetResolver.kt

@@ -15,7 +15,7 @@ import org.jetbrains.kotlin.fir.resolve.ResolutionMode
 import org.jetbrains.kotlin.fir.resolve.transformers.body.resolve.FirAbstractBodyResolveTransformerDispatcher
 import org.jetbrains.kotlin.fir.visitors.transformSingle
 
-internal abstract class LLFirAbstractBodyTargetResolver(
+internal sealed class LLFirAbstractBodyTargetResolver(
     resolveTarget: LLFirResolveTarget,
     resolvePhase: FirResolvePhase,
     protected val llImplicitBodyResolveComputationSession: LLImplicitBodyResolveComputationSession = LLImplicitBodyResolveComputationSession(),

analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/transformers/LLFirLazyResolver.kt

@@ -19,7 +19,7 @@ import org.jetbrains.kotlin.utils.exceptions.requireWithAttachment
  * @see LLFirLazyResolverRunner
  * @see LLFirTargetResolver
  */
-internal abstract class LLFirLazyResolver(val resolverPhase: FirResolvePhase) {
+internal sealed class LLFirLazyResolver(val resolverPhase: FirResolvePhase) {
     fun resolve(target: LLFirResolveTarget) {
         val resolver = createTargetResolver(target)
         requireWithAttachment(

analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/transformers/LLFirTargetResolver.kt

@@ -73,7 +73,7 @@ import org.jetbrains.kotlin.utils.exceptions.requireWithAttachment
  * @see LLFirLockProvider
  * @see FirResolvePhase
  */
-internal abstract class LLFirTargetResolver(
+internal sealed class LLFirTargetResolver(
     protected val resolveTarget: LLFirResolveTarget,
     val resolverPhase: FirResolvePhase,
     private val isJumpingPhase: Boolean = false,