0024897: Possibility of uncontrolled exit if scanner fails in ExprIntrp

0024897: Possibility of uncontrolled exit if scanner fails in ExprIntrp

Macro YY_FATAL_ERROR() is defined in ExprIntrp.lex in order to have exception instead of program exit in case of scanner error. Fixed-length string buffers are replaced by TCollection_AsciiString to avoid buffer overflow.
Some code refactoring: declarations of functions moved to header file, unused global declarations and variables removed, compiler warnings fixed or disabled, obsolete EDL file removed.
Test case for issue CR24897
Correction of MSVC compiler warning when scanner is generated using Flex 2.5.35 on Linux