cleanup (default impl, simplify code)

platform/core-api/src/com/intellij/openapi/project/Project.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2015 JetBrains s.r.o.
+ * Copyright 2000-2017 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.
@@ -88,7 +88,9 @@ public interface Project extends ComponentManager, AreaInstance {
    * @return presentable project path
    */
   @Nullable
-  String getPresentableUrl();
+  default String getPresentableUrl() {
+    return null;
+  }
 
   /**
    * <p>Returns a workspace file:

platform/core-impl/src/com/intellij/mock/MockProject.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2016 JetBrains s.r.o.
+ * Copyright 2000-2017 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.
@@ -80,13 +80,6 @@ public class MockProject extends MockComponentManager implements Project {
     return "";
   }
 
-  @Override
-  @Nullable
-  @NonNls
-  public String getPresentableUrl() {
-    return null;
-  }
-
   @Override
   @NotNull
   @NonNls

platform/platform-api/src/com/intellij/openapi/project/ProjectUtil.kt

@@ -33,7 +33,7 @@ import com.intellij.openapi.util.io.FileUtil
 import com.intellij.openapi.util.io.FileUtilRt
 import com.intellij.openapi.vfs.VirtualFile
 import com.intellij.openapi.vfs.VirtualFilePathWrapper
-import com.intellij.util.PathUtil
+import com.intellij.util.PathUtilRt
 import com.intellij.util.io.exists
 import java.nio.file.InvalidPathException
 import java.nio.file.Path
@@ -143,8 +143,7 @@ private fun Project.getPresentableFileName(): String {
     return name
   }
 
-  val location = presentableUrl!!
-  val projectName = PathUtil.getFileName(FileUtilRt.toSystemIndependentName(location))
+  val projectName = FileUtilRt.toSystemIndependentName(PathUtilRt.getFileName(presentableUrl!!))
     .toLowerCase(Locale.US)
     .removeSuffix(ProjectFileType.DOT_DEFAULT_EXTENSION)
   return FileUtil.sanitizeFileName(projectName, false)

platform/platform-impl/src/com/intellij/openapi/command/impl/DummyProject.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2016 JetBrains s.r.o.
+ * Copyright 2000-2017 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.
@@ -53,12 +53,6 @@ public class DummyProject extends UserDataHolderBase implements Project {
     return "";
   }
 
-  @Override
-  @Nullable
-  public String getPresentableUrl() {
-    return null;
-  }
-
   @Override
   @NotNull
   public String getLocationHash() {