JVM: remove StubClassBuilder and its usage

After legacy light classes were removed, the only remaining usage was in
KotlinLightClassBuilderFactory where we ran JVM backend in the
LIGHT_CLASSES mode, and that was only used from diagnostic tests to
report JVM backend diagnostics.

We don't actually need to build stubs here, so we can just use ASM's
class writer, which means that StubClassBuilder and all its dependencies
can be removed.

compiler/frontend.java/src/org/jetbrains/kotlin/fileClasses/OldPackageFacadeClassUtils.java

@@ -1,42 +0,0 @@
-/*
- * Copyright 2010-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.jetbrains.kotlin.fileClasses;
-
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.kotlin.name.FqName;
-
-public final class OldPackageFacadeClassUtils {
-    private static final String PACKAGE_CLASS_NAME_SUFFIX = "Package";
-    private static final String DEFAULT_PACKAGE_CLASS_NAME = "_Default" + PACKAGE_CLASS_NAME_SUFFIX;
-
-    private OldPackageFacadeClassUtils() {
-    }
-
-    // ex. <root> -> _DefaultPackage, a -> APackage, a.b -> BPackage
-    @NotNull
-    public static String getPackageClassName(@NotNull FqName packageFQN) {
-        if (packageFQN.isRoot()) {
-            return DEFAULT_PACKAGE_CLASS_NAME;
-        }
-        return capitalizeNonEmptyString(packageFQN.shortName().asString()) + PACKAGE_CLASS_NAME_SUFFIX;
-    }
-
-    @NotNull
-    private static String capitalizeNonEmptyString(@NotNull String s) {
-        return Character.isUpperCase(s.charAt(0)) ? s : Character.toUpperCase(s.charAt(0)) + s.substring(1);
-    }
-}