"Multiple multi function" collapse in batched tasks

**Enterprise Kapacitor 1.3.3**

When running a task with "multiple multi function" columns like this:

` SELECT non_negative_derivative(mean(*), 1s),non_negative_derivative(max(*), 1s),min(*),mean(*),max(*) FROM ...`

The derivative columns will first lookup real column names and then prefix them with `non_negative_derivative`, but then they will get collapsed into one result column per multi function column. The right most combo will get returned.

So from the example above, `non_negative_derivative(max(*), 1s) `, are the values returned and the mean values will be suppressed/overwritten.

You can fix this by adding an `as [string]` that's different for the two, like:

` SELECT non_negative_derivative(mean(*), 1s) as mean_rate,non_negative_derivative(max(*), 1s) as max_rate,min(*),mean(*),max(*) FROM ...`

But Kapacitor should be able to fix this by itself unless you name a prefix string yourself, like above. I'm not sure which way I think is best, but probably making a multi prefix string based on all chained functions, like:

`non_negative_derivative(mean(*), 1s) => non_negative_derivative_mean_[real_column_name]`

Another way could be suffixing the result with like `_[number]` or something like that

Start by reproducing the batched task using multiple multi-function expressions such as non_negative_derivative(mean(*), 1s) and non_negative_derivative(max(*), 1s), with and without explicit aliases. Trace how the derivative columns are named and collapsed, then verify that each chained-function result remains distinct while user-provided aliases still take precedence.

Written by the indexing model from the issue text.