c-regress: fix run-all.sh to avoid infinite loop

suite/regress/c-crashers/run-all.sh

 #!/bin/sh
 
-for i in `find . -type f`; do [ -x $i ] && echo "Run $i" && $i; done
+for i in `find . -not -name "*.sh" -type f`; do [ -x $i ] && echo "Run $i" && $i; done