Add FirResolution.enabled wrapper

idea/idea-analysis/src/org/jetbrains/kotlin/idea/fir/FirResolution.kt

@@ -0,0 +1,20 @@
+/*
+ * 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.idea.fir
+
+import com.intellij.ide.util.PropertiesComponent
+
+// Just a wrapper to see whether resolve works via FIR or not
+object FirResolution {
+    private const val ENABLED_BY_DEFAULT = false
+    private const val optionName = "kotlin.use.fir.resolution"
+
+    var enabled: Boolean
+        get() = PropertiesComponent.getInstance().getBoolean(optionName, ENABLED_BY_DEFAULT)
+        set(value) {
+            PropertiesComponent.getInstance().setValue(optionName, value, ENABLED_BY_DEFAULT)
+        }
+}