Fix heisenbug (#5027)

* Fix heisenbug

* [Temp] Add sleep between tests to analyze the issue.

* Change to use blocking calls

* Apply ScalaFmt

* Revert "Apply ScalaFmt"

This reverts commit 660b463

* Remove unnecessary import

* Increase the buffer size.

Author: style95

ansible/roles/nginx/templates/nginx.conf.j2

@@ -22,6 +22,7 @@ http {
 {# needed to enable keepalive to upstream controllers #}
     proxy_http_version 1.1;
     proxy_set_header Connection "";
+    proxy_buffers 16 4k;
 
 {% if controller.protocol == 'https' %}
     proxy_ssl_session_reuse on;

tests/src/test/scala/org/apache/openwhisk/core/limits/ActionLimitsTests.scala

@@ -435,7 +435,7 @@ class ActionLimitsTests extends TestHelpers with WskTestHelpers with WskActorSys
     }
 
     for (a <- 1 to 10) {
-      val run = wsk.action.invoke(name, Map("payload" -> "128".toJson))
+      val run = wsk.action.invoke(name, Map("payload" -> "128".toJson), blocking = true)
       withActivation(wsk.activation, run) { response =>
         response.response.status shouldBe "success"
         response.response.result shouldBe Some(JsObject("msg" -> "OK, buffer of size 128 MB has been filled.".toJson))

tests/src/test/scala/services/HeadersTests.scala

@@ -83,7 +83,7 @@ class HeadersTests extends FlatSpec with Matchers with ScalaFutures with WskActo
     Http().singleRequest(httpRequest, connectionContext = connectionContext)
   }
 
-  implicit val config = PatienceConfig(10 seconds, 0 milliseconds)
+  implicit val config = PatienceConfig(10 seconds, 100 milliseconds)
 
   val basePath = Path("/api/v1")
   implicit val wskprops = WskProps()