Negative numbers should also pass the test

Author: tautschnig

regression/cbmc/pointer-function-parameters-2/test.desc

@@ -5,7 +5,7 @@ main.c
 ^Test suite:$
 ^a=\(\(signed int \*\*\)NULL\), tmp\$\d+=[^,]*, tmp\$\d+=[^,]*$
 ^a=&tmp\$\d+!0, tmp\$\d+=\(\(signed int \*\)NULL\), tmp\$\d+=[^,]*$
-^a=&tmp\$\d+!0, tmp\$\d+=&tmp\$\d+!0, tmp\$\d+=([012356789][0-9]*|4[0-9]+)$
+^a=&tmp\$\d+!0, tmp\$\d+=&tmp\$\d+!0, tmp\$\d+=(-[0-9]+|[012356789][0-9]*|4[0-9]+)$
 ^a=&tmp\$\d+!0, tmp\$\d+=&tmp\$\d+!0, tmp\$\d+=4$
 ^EXIT=0$
 ^SIGNAL=0$