CMake: Replace parseCMakeCacheDotTxt() function

... by direct use of  CMakeConfig::fromFile(). It was only duplicating
checks that are done on the user side already.

Change-Id: Iaf5e89c924c2b0a9080db9fe160970bbf6e33154
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Cristian Adam <cristian.adam@qt.io>

src/plugins/cmakeprojectmanager/cmakebuildsystem.h

@@ -98,10 +98,6 @@ public:
     Utils::CommandLine commandLineForTests(const QList<QString> &tests,
                                            const QStringList &options) const final;
 
-    // Generic CMake helper functions:
-    static CMakeConfig parseCMakeCacheDotTxt(const Utils::FilePath &cacheFile,
-                                             QString *errorMessage);
-
     static bool filteredOutTarget(const CMakeBuildTarget &target);
 
     bool isMultiConfig() const;