common,w32: Refine the command line parsing for \ in quotes.
* common/t-w32-cmdline.c (test_all): Add new test cases. * common/w32-misc.c (strip_one_arg): Add arg endquote. (parse_cmdstring): Take care of backslashes in quotes.
I found some new test vectors from Microsoft.
(cherry picked from commit 20c60076866904187a09393de596deef286116f8)