Reuse generated SQL functions plans

[hatyo]

Each time we invoke a (temporary) SQL function we regenerate its plan, this is mainly done for two reasons:

• avoid identifier collisions.
• plans are mutable, the planner can alter the passed plan in a way that makes it invalid to use again.

For these reasons, we could deep-copy the function plan using a special rebase operator that assigns new identifiers as it traverses the plan and copies it.

[normen662]

Please see

public static List<? extends Reference> rebaseGraphs(@Nonnull final List<? extends Reference> refs,
                                                     @Nonnull final Memoizer memoizer,
                                                     @Nonnull final TranslationMap translationMap,
                                                     final boolean shouldSimplifyValues) {
...
}

for details. For this case, we should use new ToUniqueAliasesTranslationMap() for the translationMap parameter.