Pass environment to the testing debugger

The C++ debugger requires "environment" key.
https://code.visualstudio.com/docs/cpp/launch-json-reference

Fixes #240

src/tests.ts

@@ -128,12 +128,20 @@ export async function testDebugHandler(
     let args = [...test.cmd];
     args.shift();
 
+    const debugEnv = [];
+    /* convert from dict of key = value to array of {name: key, value: value} */
+    if (test.env instanceof Object) {
+      for (const [key, val] of Object.entries(test.env)) {
+        debugEnv.push({ name: key, value: val });
+      }
+    }
+
     let debugConfiguration = {
       name: `meson-debug-${test.name}`,
       type: debugType,
       request: "launch",
       cwd: test.workdir || sourceDir,
-      env: test.env,
+      environment: debugEnv,
       program: test.cmd[0],
       args: args,
     };