patch 8.2.5057: using gettimeofday() for timeout is very inefficient

Problem:    Using gettimeofday() for timeout is very inefficient.
Solution:   Set a platform dependent timer. (Paul Ollis, closes #10505)
diff --git a/src/testdir/test_hlsearch.vim b/src/testdir/test_hlsearch.vim
index db54ed4..8325841 100644
--- a/src/testdir/test_hlsearch.vim
+++ b/src/testdir/test_hlsearch.vim
@@ -37,6 +37,15 @@
 func Test_hlsearch_hangs()
   CheckFunction reltimefloat
 
+  " So, it turns out the Windows 7 implements TimerQueue timers differently
+  " and they can expire *before* the requested time has elapsed. So allow for
+  " the timeout occurring after 80 ms (5 * 16 (the typical clock tick)).
+  if has("win32")
+    let min_timeout = 0.08
+  else
+    let min_timeout = 0.1
+  endif
+
   " This pattern takes a long time to match, it should timeout.
   new
   call setline(1, ['aaa', repeat('abc ', 1000), 'ccc'])
@@ -45,7 +54,7 @@
   let @/ = '\%#=1a*.*X\@<=b*'
   redraw
   let elapsed = reltimefloat(reltime(start))
-  call assert_true(elapsed > 0.1)
+  call assert_true(elapsed > min_timeout)
   call assert_true(elapsed < 1.0)
   set nohlsearch redrawtime&
   bwipe!