message: [XLA] Remove '_class' attribute from compilation cache key
  This attribute is used for colocation information, and is essentially unique for most ops. It doesn't give any semantic information about the op, but does make each op look unique.
diff: @@ -205,6 +205,10 @@ Status XlaCompilationCache::CompileSingleOp(
  NameAttrList name;
  name.set_name(def.op());
  *name.mutable_attr() = def.attr();
  + // Remove the "_class" attribute from the attribute set used to create the
  + // compilation cache key. This attribute is information for the colocator
  + // and causes false uniqueness between nodes.
  + name.mutable_attr()->erase("_class");
  auto compile_op = [&](XlaCompiler* compiler,
  XlaCompiler::CompilationResult* result) {
  std::vector<DataType> result_dtypes(ctx->num_outputs());
  