[Cycle 7] "System.Net.WebException: Error: NameResolutionFailure" on second web request to certain raw IP addresses with HttpClient
This is a follow-up to Bug 41782. At least when using HttpClient as in the code example below, `ServicePoint.get_HostEntry()`  gets called 2 separate times, once for each request. On the second time, `host` is non-null and `HasTimedOut` is true, so `get_HostEntry()` returns `null` rather than returning the non-null `host`.
## Steps to replicate
Replace the IP address in the following program with a "bad" IP address that hits the problem and run the program.
public static void Main(string args)
public static void DoRequest()
var httpClient = new HttpClient();
var responseTask = httpClient.GetAsync("http://127.0.0.1");
var response = responseTask.Result;
## Regression status: regression in Cycle 7
BAD: Mono 4.6.0 (mono-4.6.0-branch/37dea728) "C8"
BAD: Mono 4.4.2 (mono-4.4.0-branch-c7sr1/b430435) "C7SR1"
GOOD: Mono 4.2.4 (explicit/71b88f3) "C6SR4"
## BAD Results
The second call to `DoRequest()` fails:
> Unhandled Exception:
> System.AggregateException: One or more errors occurred. ---> System.Net.WebException: Error: NameResolutionFailure
## GOOD Results
The app runs to completion without error.
*** Bug 42850 has been marked as a duplicate of this bug. ***
Fixed in master and Mono 4.6
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