Remove unnecessary tests in ast2firm: An if-statement always has a true_statement.
[cparser] / lextest /
drwxr-xr-x   ..
-rwxr-xr-x 246 do_tests.sh
drwxr-xr-x - legalc
drwxr-xr-x - preprocessor
drwxr-xr-x - tokenstreams
drwxr-xr-x - warnings