patch 8.0.0737: crash when X11 selection is very big

Problem:    Crash when X11 selection is very big.
Solution:   Use static items instead of allocating them.  Add callbacks.
            (Ozaki Kiichi)
diff --git a/src/testdir/shared.vim b/src/testdir/shared.vim
index e28d162..790b07b 100644
--- a/src/testdir/shared.vim
+++ b/src/testdir/shared.vim
@@ -111,14 +111,15 @@
 " Wait for up to a second for "expr" to become true.
 " Return time slept in milliseconds.  With the +reltime feature this can be
 " more than the actual waiting time.  Without +reltime it can also be less.
-func WaitFor(expr)
+func WaitFor(expr, ...)
+  let timeout = get(a:000, 0, 1000)
   " using reltime() is more accurate, but not always available
   if has('reltime')
     let start = reltime()
   else
     let slept = 0
   endif
-  for i in range(100)
+  for i in range(timeout / 10)
     try
       if eval(a:expr)
 	if has('reltime')
@@ -133,7 +134,7 @@
     endif
     sleep 10m
   endfor
-  return 1000
+  return timeout
 endfunc
 
 " Wait for up to a given milliseconds.
diff --git a/src/testdir/test_quotestar.vim b/src/testdir/test_quotestar.vim
index b053260..b7d3158 100644
--- a/src/testdir/test_quotestar.vim
+++ b/src/testdir/test_quotestar.vim
@@ -88,6 +88,18 @@
   call WaitFor('@* == "yes"')
   call assert_equal('yes', @*)
 
+  " Handle the large selection over 262040 byte.
+  let length = 262044
+  let sample = 'a' . repeat('b', length - 2) . 'c'
+  let @* = sample
+  call WaitFor('remote_expr("' . name . '", "len(@*) >= ' . length . '", "", 1)', 3000)
+  let res = remote_expr(name, "@*", "", 2)
+  call assert_equal(length, len(res))
+  " Check length to prevent a large amount of output at assertion failure.
+  if length == len(res)
+    call assert_equal(sample, res)
+  endif
+
   if has('unix') && has('gui') && !has('gui_running')
     let @* = ''