sh testsuite: add tests for exitcode on failure to exec

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/ash_test/ash-misc/exitcode_EACCES.tests b/shell/ash_test/ash-misc/exitcode_EACCES.tests
new file mode 100755
index 0000000..26b5c61
--- /dev/null
+++ b/shell/ash_test/ash-misc/exitcode_EACCES.tests
@@ -0,0 +1,2 @@
+./
+echo $?