This function numifies the field width string in something like
printf "%10f". It handles integer overflow itself, so suppress
ASan warnings, e.g.
sv.c:10716:26: runtime error: signed integer overflow:
922337203 * 10 cannot be represented in type 'int'
# (UVs normally, IVs with 'use integer')
fun:Perl_pp_left_shift
+
+# this function numifies the field width in eg printf "%10f".
+# It has its own overflow detection, so don't warn about it
+
+fun:S_expect_number