Count record reads performed by the IDX code.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@60019 65644016-39b1-43b1-bf79-96bc8fe82c15
Misc

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@60020 65644016-39b1-43b1-bf79-96bc8fe82c15
Refactored the shared cache checks. Optimized the shared counter for SS.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@60021 65644016-39b1-43b1-bf79-96bc8fe82c15
Correction.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@60022 65644016-39b1-43b1-bf79-96bc8fe82c15