Fixed CORE-4091 (Incorrect full join result with ROW_NUMBER() Function in CTE) and one part of CORE-4083 (full outer join in subrequest with coalesce).

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@58001 65644016-39b1-43b1-bf79-96bc8fe82c15
Simple fix for CORE-4093: Server crashes while converting an overscaled numeric to a string. It assumes the resulting string being limited in length by the scale (value <= 128). A more generic solution (e.g. disallow overflowing scales) would be appreciated for the trunk.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@58003 65644016-39b1-43b1-bf79-96bc8fe82c15
Corrected the target buffer length.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@58006 65644016-39b1-43b1-bf79-96bc8fe82c15