Tweaks for review comments.

pkg/analysis_server/test/index/b_plus_tree_test.dart

Index: pkg/analysis_server/test/index/b_plus_tree_test.dart
diff --git a/pkg/analysis_server/test/index/b_plus_tree_test.dart b/pkg/analysis_server/test/index/b_plus_tree_test.dart
index bb8ff336977dd84faef8bc2c458d4e9cb7e07830..a3abcce85fbef9702c008af8dbb37fcaef9186ff 100644
--- a/pkg/analysis_server/test/index/b_plus_tree_test.dart
+++ b/pkg/analysis_server/test/index/b_plus_tree_test.dart
@@ -642,7 +642,7 @@ INode {
     int tryCount = 1000;
     Set<int> keys = new Set<int>();
     {
-      Random random = new Random();
+      Random random = new Random(37);
       for (int i = 0; i < tryCount; i++) {
         int key = random.nextInt(maxKey);
         keys.add(key);
@@ -655,7 +655,7 @@ INode {
     }
     // remove random keys
     {
-      Random random = new Random();
+      Random random = new Random(37);
       for (int key in new Set<int>.from(keys)) {
         if (random.nextBool()) {
           keys.remove(key);