Bug 1541508 - Use Services.env in memory/ r=mccr8

Differential Revision: https://phabricator.services.mozilla.com/D160141

memory/replace/dmd/test/test_dmd.js

@@ -11,10 +11,7 @@ const { FileUtils } = ChromeUtils.importESModule(
 );
 
 // The xpcshell test harness sets PYTHON so we can read it here.
-var gEnv = Cc["@mozilla.org/process/environment;1"].getService(
-  Ci.nsIEnvironment
-);
-var gPythonName = gEnv.get("PYTHON");
+var gPythonName = Services.env.get("PYTHON");
 
 // If we're testing locally, the executable file is in "CurProcD". Otherwise,
 // it is in another location that we have to find.
@@ -137,7 +134,7 @@ function run_test() {
   // in-place (to fix stacks) when it runs dmd.py, and that's not safe to do
   // asynchronously.
 
-  gEnv.set("DMD", "1");
+  Services.env.set("DMD", "1");
 
   runProcess(gDmdTestFile, []);