Increate test timeouts for ServersCheckerTest

[sleshchenko]

What does this PR do?

From time to time these tests fail on our CI job.
I'm able to reproduce this issue locally if my laptop is quite loaded with another process like maven build. And as we can see the first test takes the most time.

I did not find any information about why it may happen but I assume that it's related to memory allocation.
I wrote a simple test that does nothing except N Objects

  private static final int N = 10_000_000;

  @Test(invocationCount = 40)
  public void doNothing() throws Exception {
    List<Object> list = new ArrayList<>();
    for(int i = 0; i< N; i++) {
      list.add(new Object());
    }
  }

and it's what I get:

1. N = 10_000
   
   I assume that it's a situation similar to what we have in ServersCheckerTest.java, when not much memory is needed and the first test always takes the most time. I assume that the process during the first test allocates some amount of memory and further tests just reuse it.
2. N = 10_000_000
   
   I don't have a clear explanation of why 2nd and 3rd take the most time but it's not really needed.
   My testing is not accurate at all and its purpose was just to show that using timeout needs additional care since invocation time may take different time depending on which it will be run(1,2,3,...), which time(a system is loaded, a garbage collector is active).

I believe 5 seconds should be even more than enough for tests to be stable.
In the pessimistic scenario (when there is an error in code or tests) we may pay 7*5=35 seconds of build time, but such a situation must happen only feature branch, where code is broken but not in master.

What issues does this PR fix or reference?

N/A

Release Notes

N/A

Docs PR

N/A

[che-bot]

E2E Happy path tests of Eclipse Che Single User on K8S (minikube v1.1.1) has been successful:

• build details
• logs and configs
• "che-server" docker image: maxura/che-server:15032

[sleshchenko]

ci-build

[che-bot]

E2E Happy path tests of Eclipse Che Single User on K8S (minikube v1.1.1) has been successful:

• build details
• logs and configs
• "che-server" docker image: maxura/che-server:15032

[che-bot]

E2E tests of Eclipse Che Multiuser on OCP has been successful:

• Build details
• Test report
• docker image: eclipseche/che-server:15032

[che-bot]

E2E tests of Eclipse Che Multiuser on OCP has been successful:

• Build details
• Test report
• docker image: eclipseche/che-server:15032