This ensures that a command such as
$ ninja tst_qlocale && ninja tst_qlocale_check
will automagically build the syslocaleapp program that the test runs
from a subtest. Similar for testlib's selftests and tst_QProcess.
As a drive-by, pruned some legacy comments from when CMakeLists.txt
files were generated from .pro files.
Change-Id: I67691a8175aaef124d4104cf1898193993408bdf
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Andrei Golubev <andrei.golubev@qt.io>