CMake: Split big plugin tests into smaller pieces

... which can then live closer to the tested code.

Change-Id: Icd975a76424ea2258c1bb93afdbaabdf1959340a
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>

src/plugins/cmakeprojectmanager/cmakeparser.h

@@ -53,4 +53,8 @@ private:
     CallStackLine m_errorOrWarningLine;
 };
 
+#ifdef WITH_TESTS
+namespace Internal { QObject *createCMakeParserTest(); }
+#endif
+
 } // CMakeProjectManager