FIR IDE: remove enabled/disable FirResolution by registry

This separation is made based on plugins now

idea/idea-fir/tests/org/jetbrains/kotlin/checkers/AbstractFirPsiCheckerTest.kt

@@ -17,7 +17,6 @@ abstract class AbstractFirPsiCheckerTest : AbstractPsiCheckerTest() {
 
     override fun setUp() {
         super.setUp()
-        FirResolution.enabled = true
     }
 
     override fun doTest(filePath: String) {
@@ -48,7 +47,6 @@ abstract class AbstractFirPsiCheckerTest : AbstractPsiCheckerTest() {
     }
 
     override fun tearDown() {
-        FirResolution.enabled = false
         super.tearDown()
     }
 }

idea/idea-fir/tests/org/jetbrains/kotlin/idea/resolve/AbstractFirReferenceResolveTest.kt

@@ -6,7 +6,6 @@
 package org.jetbrains.kotlin.idea.resolve
 
 import org.jetbrains.kotlin.idea.completion.test.configureWithExtraFile
-import org.jetbrains.kotlin.idea.fir.low.level.api.FirResolution
 import org.jetbrains.kotlin.idea.test.KotlinLightProjectDescriptor
 import org.jetbrains.kotlin.idea.test.KotlinWithJdkAndRuntimeLightProjectDescriptor
 import org.jetbrains.kotlin.test.InTextDirectivesUtils
@@ -19,7 +18,6 @@ abstract class AbstractFirReferenceResolveTest : AbstractReferenceResolveTest()
 
     override fun setUp() {
         super.setUp()
-        FirResolution.enabled = true
     }
 
     override fun doTest(path: String) {
@@ -37,7 +35,6 @@ abstract class AbstractFirReferenceResolveTest : AbstractReferenceResolveTest()
     }
 
     override fun tearDown() {
-        FirResolution.enabled = false
         super.tearDown()
     }
 }

idea/idea-frontend-fir/idea-fir-low-level-api/src/org/jetbrains/kotlin/idea/fir/low/level/api/FirResolution.kt

@@ -1,25 +0,0 @@
-/*
- * Copyright 2010-2020 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.idea.fir.low.level.api
-
-import com.intellij.openapi.util.registry.Registry
-
-// Just a wrapper to see whether resolve works via FIR or not
-object FirResolution {
-    private const val optionName = "kotlin.use.fir.resolution"
-
-    private val initialEnabledValue: Boolean by lazy {
-        Registry.`is`(optionName, /* defaultValue = */ true)
-    }
-
-    private var changedEnabledValue: Boolean? = null
-
-    var enabled: Boolean
-        get() = changedEnabledValue ?: initialEnabledValue
-        set(value) {
-            changedEnabledValue = value
-        }
-}

idea/resources/META-INF/extensions/ide.xml

@@ -113,10 +113,7 @@
                      description="Add all transitive dependencies on MPP modules when Android project is imported"
                      defaultValue="true"
                      restartRequired="false"/>
-        <registryKey key="kotlin.use.fir.resolution"
-                     description="Use Kotlin resolution via frontend IR for reference resolve and diagnostics in IDEA"
-                     defaultValue="false"
-                     restartRequired="true"/>
+
         <registryKey key="kotlin.gradle.scripts.useIdeaProjectImport"
                      description="Use IDEA project import mechanics to load Kotlin Gradle scripts configuration"
                      defaultValue="false"