git: openjdk/loom: fibers: fix build on Windows: unistd.h and usleep are absent

[duke]

Changeset: a7be7eac
Author:    Serguei Spitsyn <serguei.spitsyn at oracle.com>
Date:      2021-04-01 02:02:02 +0000
URL:       https://git.openjdk.java.net/loom/commit/a7be7eac

fix build on Windows: unistd.h and usleep are absent

! test/hotspot/jtreg/serviceability/jvmti/SuspendWithCurrentThread/libSuspendWithCurrentThread.cpp
! test/lib/jdk/test/lib/jvmti/jvmti_common.h