tests: convert tests to new style

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

tests/ops/exec/undefined/with_pkg_def/cue.mod/pkg/test.dagger.io/def/main.cue

@@ -1,15 +1,14 @@
 package def
 
+import "alpha.dagger.io/dagger/op"
+
 #dang: string
 
 #up: [
-	{
-		do:  "fetch-container"
+	op.#FetchContainer & {
 		ref: "alpine"
 	},
-	{
-		do:  "exec"
-		dir: "/"
+	op.#Exec & {
 		args: ["sh", "-c", """
 			echo success
 			"""]

tests/ops/exec/undefined/with_pkg_mandatory/cue.mod/pkg/test.dagger.io/nonoptional/main.cue

@@ -1,15 +1,14 @@
 package nonoptional
 
+import "alpha.dagger.io/dagger/op"
+
 dang: string
 
 #up: [
-	{
-		do:  "fetch-container"
+	op.#FetchContainer & {
 		ref: "alpine"
 	},
-	{
-		do:  "exec"
-		dir: "/"
+	op.#Exec & {
 		args: ["sh", "-c", """
 			echo "This test SHOULD fail, because this SHOULD be executed"
 			exit 1

tests/ops/exec/undefined/with_pkg_optional/cue.mod/pkg/test.dagger.io/optional/main.cue

@@ -1,15 +1,14 @@
 package optional
 
+import "alpha.dagger.io/dagger/op"
+
 dang?: string
 
 #up: [
-	{
-		do:  "fetch-container"
+	op.#FetchContainer & {
 		ref: "alpine"
 	},
-	{
-		do:  "exec"
-		dir: "/"
+	op.#Exec & {
 		args: ["sh", "-c", """
 			echo success
 			"""]