xml dump: Added function attribute in scope
Fixed #5978 (false positive: Array 'm_pool_vector[-1]' accessed at index 0, which is out of bounds.)
xml dump: added 'astIsFloat' utility function in cppcheckdata.py
htmlreport: fix #5998, crash on some files with "UnicodeDecodeError".
Now we don't generate a html-code page for the respective files but continue execution.