Revert "tests: define equals & hashcode for the MockVirtualFile"

Several tests rely on the fact that MockVirtualFiles should be compared only by equals.

This reverts commit 9d6794d2

platform/testFramework/src/com/intellij/mock/MockVirtualFile.java

@@ -126,20 +126,6 @@ public class MockVirtualFile extends VirtualFile {
     return VfsUtilCore.toVirtualFileArray(myChildren);
   }
 
-  @Override
-  public boolean equals(Object o) {
-    if (this == o) return true;
-    if (o == null || getClass() != o.getClass()) return false;
-
-    MockVirtualFile file = (MockVirtualFile)o;
-    return getPath().equals(file.getPath());
-  }
-
-  @Override
-  public int hashCode() {
-    return getPath().hashCode();
-  }
-
   @NotNull
   @Override
   public OutputStream getOutputStream(Object requestor, long newModificationStamp, long newTimeStamp) throws IOException {