Extract some classes from descriptors module to :core:common

This is needed to remove dependencies from fir modules to
  `:core:descriptors` module

What was extracted:
- Modality
- ClassKind
- org.jetbrains.kotlin.name package

core/descriptors.common/build.gradle.kts

@@ -0,0 +1,24 @@
+plugins {
+    kotlin("jvm")
+    id("jps-compatible")
+}
+
+jvmTarget = "1.6"
+javaHome = rootProject.extra["JDK_16"] as String
+
+dependencies {
+    compile(project(":core:util.runtime"))
+    compile(project(":core:type-system"))
+    compile(kotlinStdlib())
+    compile(project(":kotlin-annotations-jvm"))
+}
+
+sourceSets {
+    "main" { projectDefault() }
+    "test" {}
+}
+
+tasks.withType<JavaCompile> {
+    sourceCompatibility = "1.6"
+    targetCompatibility = "1.6"
+}

core/descriptors.common/src/org/jetbrains/kotlin/descriptors/Modality.kt

@@ -0,0 +1,26 @@
+/*
+ * 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.descriptors
+
+// For sealed classes, isOverridable is false but isOverridableByMembers is true
+enum class Modality {
+    // THE ORDER OF ENTRIES MATTERS HERE
+    FINAL,
+    // NB: class can be sealed but not function or property
+    SEALED,
+    OPEN,
+    ABSTRACT;
+
+    companion object {
+
+        // NB: never returns SEALED
+        fun convertFromFlags(abstract: Boolean, open: Boolean): Modality {
+            if (abstract) return ABSTRACT
+            if (open) return OPEN
+            return FINAL
+        }
+    }
+}

core/descriptors/build.gradle.kts

@@ -7,6 +7,7 @@ jvmTarget = "1.6"
 javaHome = rootProject.extra["JDK_16"] as String
 
 dependencies {
+    compile(project(":core:descriptors.common"))
     compile(project(":core:util.runtime"))
     compile(project(":core:type-system"))
     compile(kotlinStdlib())

core/descriptors/src/org/jetbrains/kotlin/descriptors/ModalityUtils.kt

@@ -18,26 +18,6 @@ package org.jetbrains.kotlin.descriptors
 
 import org.jetbrains.kotlin.resolve.DescriptorUtils
 
-// For sealed classes, isOverridable is false but isOverridableByMembers is true
-enum class Modality {
-    // THE ORDER OF ENTRIES MATTERS HERE
-    FINAL,
-    // NB: class can be sealed but not function or property
-    SEALED,
-    OPEN,
-    ABSTRACT;
-
-    companion object {
-
-        // NB: never returns SEALED
-        fun convertFromFlags(abstract: Boolean, open: Boolean): Modality {
-            if (abstract) return ABSTRACT
-            if (open) return OPEN
-            return FINAL
-        }
-    }
-}
-
 val CallableMemberDescriptor.isOverridable: Boolean
     get() = visibility != Visibilities.PRIVATE
             && modality != Modality.FINAL

core/descriptors/src/org/jetbrains/kotlin/types/AbstractClassTypeConstructor.java

@@ -58,7 +58,7 @@ public abstract class AbstractClassTypeConstructor extends AbstractTypeConstruct
     @Override
     public final boolean isFinal() {
         ClassDescriptor descriptor = getDeclarationDescriptor();
-        return ModalityKt.isFinalClass(descriptor) && !descriptor.isExpect();
+        return ModalityUtilsKt.isFinalClass(descriptor) && !descriptor.isExpect();
     }
 
     @NotNull