Refactor test servers to make them less global.

test/get/hosted/avoid_network_requests_test.dart

Index: test/get/hosted/avoid_network_requests_test.dart
diff --git a/test/get/hosted/avoid_network_requests_test.dart b/test/get/hosted/avoid_network_requests_test.dart
index 69afd64e93de6d3b7aa15e8ad49cc98215cfcece..54647e9ccd191bc72a48cd414f1c616170eb6627 100644
--- a/test/get/hosted/avoid_network_requests_test.dart
+++ b/test/get/hosted/avoid_network_requests_test.dart
@@ -27,7 +27,7 @@ main() {
 
     // Clear the cache. We don't care about anything that was served during
     // the initial get.
-    getRequestedPaths();
+    globalServer.clearRequestedPaths();
 
     // Add "bar" to the dependencies.
     d.appDir({
@@ -45,7 +45,7 @@ main() {
 
     // The get should not have done any network requests since the lock file is
     // up to date.
-    getRequestedPaths().then((paths) {
+    globalServer.requestedPaths.then((paths) {
       expect(paths, unorderedEquals([
         // Bar should be requested because it's new, but not foo.
         "api/packages/bar",