Retry POST_Expect100Continue_Get100Continue (#57374)

For #57373

Author: amcasey

eng/test-configuration.json

@@ -11,6 +11,7 @@
     {"testName": {"contains": "CanLaunchPhotinoWebViewAndClickButton"}},
     {"testName": {"contains": "CheckInvalidHostingModelParameter"}},
     {"testName": {"contains": "CanSendAndReceiveUserMessagesFromMultipleConnectionsWithSameUser"}},
+    {"testName": {"contains": "POST_Expect100Continue_Get100Continue"}},
     {"testAssembly": {"contains": "IIS"}},
     {"testAssembly": {"contains": "Template"}},
     {"failureMessage": {"contains":"(Site is started but no worker process found)"}},