Only test staticFilesByArch in > Meteor 1.9

tests/hijack/webapp.js

@@ -93,6 +93,22 @@ if (httpMonitoringEnabled) {
       test.equal(req.__kadiraInfo.trace.events[0][2].body, expected);
     });
 
+  Tinytest.add(
+    'Webapp - static middleware',
+    function (test) {
+      const result = HTTP.get(Meteor.absoluteUrl('global-imports.js'));
+      test.isTrue(result.content.includes('Package['));
+      let payload = Kadira.models.http.buildPayload();
+
+      let staticMetrics = payload.httpMetrics[0].routes['GET-<static file>'];
+      test.isTrue(staticMetrics.count > 0);
+    });
+}
+
+if (releaseParts[0] > 1 ||
+  (releaseParts[0] === 1 && releaseParts[1] > 8)) {
+  // Meteor 1.8.1 and newer started replacing staticFilesByArch instead of
+  // mutating the existing object
   Tinytest.add(
     'Webapp - use latest staticFilesByArch',
     function (test) {
@@ -111,15 +127,4 @@ if (httpMonitoringEnabled) {
 
       WebAppInternals.staticFilesByArch = origStaticFiles;
     });
-
-  Tinytest.add(
-    'Webapp - static middleware',
-    function (test) {
-      const result = HTTP.get(Meteor.absoluteUrl('global-imports.js'));
-      test.isTrue(result.content.includes('Package['));
-      let payload = Kadira.models.http.buildPayload();
-
-      let staticMetrics = payload.httpMetrics[0].routes['GET-<static file>'];
-      test.isTrue(staticMetrics.count > 0);
-    });
 }