Move UL compiler plugin support to separate extension point

compiler/frontend/src/org/jetbrains/kotlin/extensions/LightClassApplicabilityCheckExtension.kt

@@ -1,39 +0,0 @@
-/*
- * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
- * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
- */
-
-package org.jetbrains.kotlin.extensions
-
-import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
-import org.jetbrains.kotlin.psi.KtDeclaration
-
-enum class LightClassApplicabilityType {
-    LightClass,
-    UltraLightClass
-}
-
-/**
- * This extension point needs to be implemented by the Kotlin compiler plugins in case they change the requested declaration (i.e. producing synthetic parts)
- * with backend extension points. The light class provider will request this EP to check either to create LightClass or UltraLight class implementations.
- * @see org.jetbrains.kotlin.extensions.DeclarationAttributeAltererExtension
- * @see org.jetbrains.kotlin.codegen.extensions.ExpressionCodegenExtension
- */
-interface LightClassApplicabilityCheckExtension {
-    companion object : ProjectExtensionDescriptor<LightClassApplicabilityCheckExtension>(
-        "org.jetbrains.kotlin.lightClassApplicabilityCheckExtension",
-        LightClassApplicabilityCheckExtension::class.java
-    )
-
-    /**
-     * This method should return LightClass if any changes in Kotlin declarations is going to be produced during JVM-backend code generation.
-     * This method ought to be as fast as possible but never return UltraLightClass when not sure.
-     * Next advice could be given to make best:
-     * 1) Try to cover as much cases as possible without forcing descriptor evaluation
-     * 2) After you've forced descriptor evaluation, ideally, you should never return LightClass while in fact no synthetic parts going to be generated
-     * 3) So, you should force descriptor evaluation only if you're sure that you will be able to return UltraLightClass significantly more often
-     * @see org.jetbrains.kotlin.noarg.ide.IdeNoArgApplicabilityExtension
-     * @see org.jetbrains.kotlin.android.parcel.IDEParcelableApplicabilityExtension
-     */
-    fun checkApplicabilityType(declaration: KtDeclaration, descriptor: Lazy<DeclarationDescriptor?>): LightClassApplicabilityType
-}