Fix uninitialized access

When an identifier is made from an empty string, the constructor still
tries accessing the first character to populate a cache. This leads to
access of uninitialized data, and wrong data in the cache. This causes
no wrong behavior though except unuseful data in the cache.

Change-Id: Ice9f10b08306799b160f8b95b76bd056f29d228d
Reviewed-by: Michael Bruning <michael.bruning@digia.com>
Support building QtTestBrowser without QtTestSupport

Use the same flags for QtTestBrowser that MiniBrowser uses to build
without webkit's QtTestSupport.

Change-Id: I0b31b1253b5014393a472286ffc6674efc64e753
Reviewed-by: Michael Bruning <michael.bruning@digia.com>