add ash testcases

shell/ash_test/ash-invert/invert.right

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shell/ash_test/ash-invert/invert.tests

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+# tests of return value inversion
+# placeholder for future expansion
+
+# user subshells (...) did this wrong in bash versions before 2.04
+
+! ( echo hello | grep h >/dev/null 2>&1 ); echo $?
+! echo hello | grep h >/dev/null 2>&1 ; echo $?
+
+! true ; echo $?
+! false; echo $?
+
+! (false) ; echo $?
+! (true); echo $?
+
+! true | false ; echo $?
+! false | true ; echo $?
+
+! (true | false) ; echo $?
+! (false | true) ; echo $?