Fixed installation of corelib tests

Fixed installation of corelib tests

In .pro files, removed wince/symbian-specific DEPLOYMENT cases and
replaced them with TESTDATA where appropriate.

In .cpp files, removed SRCDIR and relative paths to testdata and
replaced them with the QFINDTESTDATA macro where appropriate.

Modified test helper apps/libs to install themselves under the test
they relate to.

This change allows corelib tests to be correctly installed, along with
their testdata, via `make install'.

Change-Id: I5e202e2f3b577af7e39072d5c9fe13e0ca125304
Reviewed-by: Jason McDonald <jason.mcdonald@nokia.com>