misc

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@58192 65644016-39b1-43b1-bf79-96bc8fe82c15
A cleanup and a few improvements :
- ability to wait with finite timeout
- separate counts of waiting readers and writers
- two interlocked operations are needed when lock granted to a waiting readers (despite of its amount)


git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@58193 65644016-39b1-43b1-bf79-96bc8fe82c15
Implement wait with timeout for page buffer's latches.
Note, engine passes timeout as negative seconds, while sync objects works with positive milliseconds.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@58194 65644016-39b1-43b1-bf79-96bc8fe82c15