ash testsuite: add most of hust tests which pass for ash

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

shell/ash_test/ash-misc/exit1.tests

@@ -0,0 +1,4 @@
+trap "echo Not shown" EXIT
+(exit)  # must be silent
+trap "echo Once; exit" EXIT
+{ exit; }