Revert for commit 999394b01c46e59836d7599b8b7c0354e5de113a + fix.

RewriteRuleSubtreeStream now contains cloned trees.
Fix fixes this case:

unpivot_in_elements
    :   (    column_name
        |    LEFT_PAREN column_name (COMMA column_name)* RIGHT_PAREN
        )
        (     as_key
         (    constant
         |    (LEFT_PAREN)=> LEFT_PAREN constant (COMMA constant)* RIGHT_PAREN
         )
        )?
        -> column_name+ ^(PIVOT_ALIAS constant+)?
    ;

The AST tree contains multiple instances of "column_name".
RewriteRuleSubtreeStream can not contain reference into matched tree as it would get overwritten
in every "loop". Parse tree value can not be moved into RewriteRuleSubtreeStream as this could be also
used in rewrite allias (also instance of the RewriteRuleSubtreeStream).