SynEdit: Avoid highlighter scanning twice, due to trailing space changes

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@43159 4005530d-fff6-0310-9dd1-cebe43e6787f
SourceEdit: Set ifdef (on tab change) after dec-paintlock)

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@43160 4005530d-fff6-0310-9dd1-cebe43e6787f