Flagging a few census tests as flaky.

build.json

@@ -810,6 +810,7 @@
     },
     {
       "name": "census_statistics_multiple_writers_test",
+      "flaky": true,
       "build": "test",
       "language": "c",
       "src": [
@@ -824,6 +825,7 @@
     },
     {
       "name": "census_statistics_performance_test",
+      "flaky": true,
       "build": "test",
       "language": "c",
       "src": [
@@ -838,6 +840,7 @@
     },
     {
       "name": "census_statistics_quick_test",
+      "flaky": true,
       "build": "test",
       "language": "c",
       "src": [

tools/run_tests/tests.json

@@ -65,7 +65,7 @@
     ]
   }, 
   {
-    "flaky": false, 
+    "flaky": true, 
     "language": "c", 
     "name": "census_statistics_multiple_writers_test", 
     "platforms": [
@@ -74,7 +74,7 @@
     ]
   }, 
   {
-    "flaky": false, 
+    "flaky": true, 
     "language": "c", 
     "name": "census_statistics_performance_test", 
     "platforms": [
@@ -83,7 +83,7 @@
     ]
   }, 
   {
-    "flaky": false, 
+    "flaky": true, 
     "language": "c", 
     "name": "census_statistics_quick_test", 
     "platforms": [