Deduplicate executor code (#2494)

There are many places in the executor codebase which evaluate an AST expression and produce a KCL memory item. They could be deduplicated and put into one central location.

Fixes <https://github.com/KittyCAD/modeling-app/issues/1931>.

src/wasm-lib/tests/executor/main.rs

@@ -128,6 +128,15 @@ async fn serial_test_lego() {
     twenty_twenty::assert_image("tests/executor/outputs/lego.png", &result, 0.999);
 }
 
+#[tokio::test(flavor = "multi_thread")]
+async fn serial_test_pipe_as_arg() {
+    let code = include_str!("inputs/pipe_as_arg.kcl");
+    let result = execute_and_snapshot(code, kcl_lib::settings::types::UnitLength::Mm)
+        .await
+        .unwrap();
+    twenty_twenty::assert_image("tests/executor/outputs/pipe_as_arg.png", &result, 0.999);
+}
+
 #[tokio::test(flavor = "multi_thread")]
 async fn serial_test_pentagon_fillet_sugar() {
     let code = include_str!("inputs/pentagon_fillet_sugar.kcl");