Test for presence of shadowenv binary before running Shadowenv suite

Not all non-Shopify developer environments have a version of shadowenv
installed. In those circumstances, skip the suite with a console warning.

Part of #2877

vscode/src/test/suite/ruby/shadowenv.test.ts

@@ -14,13 +14,20 @@ import { LOG_CHANNEL, asyncExec } from "../../../common";
 import { RUBY_VERSION } from "../../rubyVersion";
 import * as common from "../../../common";
 
-suite("Shadowenv", () => {
+suite("Shadowenv", async () => {
   if (os.platform() === "win32") {
     // eslint-disable-next-line no-console
     console.log("Skipping Shadowenv tests on Windows");
     return;
   }
 
+  try {
+    await asyncExec("shadowenv --version");
+  } catch {
+    console.log("Skipping Shadowenv tests because no `shadowenv` found");
+    return;
+  }
+
   let rootPath: string;
   let workspacePath: string;
   let workspaceFolder: vscode.WorkspaceFolder;