fix: attempt to fix intermittent test failures

[salmanm]

Builds are still not very stable on windows CI.
Although we tried running on windows machine locally but could never see a test fail.

In httpClient.test.js

It seems like these two tests in httpClient.test.js are failing intermittently.

• client should emit a timeout when no response is received
• client should emit 2 timeouts when no responses are received

This PR increases wait time from 2500 to 2800, just so slow windows boxes don't choke up.

in runRate.test.js

All 3 scenarios of the following test are failing intermittently.

• run should only send the expected number of requests per second

I presume the duration may be coming as slightly more than 4.5 seconds due to slow windows box and becomes 5 due to Math.round. But we're asserting it with 4, so I've changed it to Math.floor instead.

[mcollina]

lgtm, might be the right time!