tests: move tests top-level

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

tests/exec/error/main.cue

@@ -0,0 +1,12 @@
+package testing
+
+#dagger: compute: [
+	{
+		do:  "fetch-container"
+		ref: "alpine"
+	},
+	{
+		do: "exec"
+		args: ["erroringout"]
+	},
+]