Lua: Add waitms test

Change-Id: I281f0a5595140ff450e1a30e189286e1a5d8cf9d
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>

src/plugins/luatests/luatests/tst_utils.lua

@@ -20,7 +20,15 @@ local function testSearchInPath()
     print("Hostname found at:", result)
 end
 
+local function testWaitMs()
+    local u = require("Utils")
+    print("Starting to wait ...")
+    a.wait(u.waitms(1000))
+    print("About a second should have elapsed now.")
+end
+
 return {
     testDirEntries = testDirEntries,
     testSearchInPath = testSearchInPath,
+    testWaitMs = testWaitMs,
 }