Fix URLConnectionTest.test_setReadTimeoutI on host test

This was failing because the test assumes that read will not complete
within 1ms, while it is still possible, especially on host tests.

This patch introduces a minimum time delay before the TestWebServer
sends data.

Bug: 32363029
Test: org.apache.harmony.luni.tests.java.net.URLConnectionTest#test_setReadTimeoutI under host tests
Change-Id: Ibb4e2125f99b0544d0f09331b4ab9b0448b14035