Preprocessor Enginge: fix bug in pp-engine.cpp

Preprocessor variables __LINE__,__FILE__,__TIME__,__DATE__ where destroying
the following systems when affected variables were standing  within the
same line with those variables:
* highlighting
* refactoring
* local renaming

Task-number: QTCREATORBUG-8036
Change-Id: I1a4b919d15812872ca5a8e63b1031ec1ab144c22
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>