Merge #16117: util: Replace boost sleep with std sleep

fae86c38bc util: Remove unused MilliSleep (MarcoFalke)
fa9af06d91 scripted-diff: Replace MilliSleep with UninterruptibleSleep (MarcoFalke)
fa4620be78 util: Add UnintrruptibleSleep (MarcoFalke)

Pull request description:

  We don't use the interruptible feature of boost's sleep anywhere, so replace it with the sleep in `std::thread`

ACKs for top commit:
  ajtowns:
    ACK fae86c38bc quick code review
  practicalswift:
    ACK fae86c38bc -- patch looks correct
  sipa:
    Concept and code review ACK fae86c38bc
  fanquake:
    ACK fae86c38bc - note that an instance of `DHAVE_WORKING_BOOST_SLEEP_FOR` was missed in the [linter](https://github.com/bitcoin/bitcoin/blob/master/test/lint/extended-lint-cppcheck.sh#L69), but that can be cleaned up later.

Tree-SHA512: 7c0f8eb197664b9f7d9fe6c472c77d384f11c797c913afc31de4b532e3b4fd9ea6dd174f92062ff9d1ec39b25e0900ca7c597435add87f0f2477d9557204848c

src/test/scheduler_tests.cpp

@@ -4,6 +4,7 @@
 
 #include <random.h>
 #include <scheduler.h>
+#include <util/time.h>
 
 #include <boost/thread.hpp>
 #include <boost/test/unit_test.hpp>
@@ -23,18 +24,6 @@ static void microTask(CScheduler& s, boost::mutex& mutex, int& counter, int delt
     }
 }
 
-static void MicroSleep(uint64_t n)
-{
-#if defined(HAVE_WORKING_BOOST_SLEEP_FOR)
-    boost::this_thread::sleep_for(boost::chrono::microseconds(n));
-#elif defined(HAVE_WORKING_BOOST_SLEEP)
-    boost::this_thread::sleep(boost::posix_time::microseconds(n));
-#else
-    //should never get here
-    #error missing boost sleep implementation
-#endif
-}
-
 BOOST_AUTO_TEST_CASE(manythreads)
 {
     // Stress test: hundreds of microsecond-scheduled tasks,
@@ -81,7 +70,7 @@ BOOST_AUTO_TEST_CASE(manythreads)
     for (int i = 0; i < 5; i++)
         microThreads.create_thread(std::bind(&CScheduler::serviceQueue, &microTasks));
 
-    MicroSleep(600);
+    UninterruptibleSleep(std::chrono::microseconds{600});
     now = boost::chrono::system_clock::now();
 
     // More threads and more tasks: