Add script for timing sign-unplace.

unplace.vim

@@ -0,0 +1,26 @@
+" Measure how long it takes to unplace signs.
+"
+" Source this file with `:source %` or `vim -S unplace.vim`
+
+
+let num = 500
+sign define Foo text=*
+
+new
+
+call append(0, range(1, num))
+
+for i in range(1, num)
+  execute "sign place ".i." line=".i." name=Foo buffer=".bufnr('')
+endfor
+
+let start = reltime()
+for i in range(1, num)
+  execute "sign unplace ".i
+endfor
+let elapsed = reltime(start)
+
+bdelete!
+
+echom split(reltimestr(elapsed))[0]."s to remove ".num." signs"
+echom string(reltimefloat(elapsed) * 1000 / num).' ms/sign'