ClangFormat: Start to use new file management

- Indenter uses .clang-format file from a dir of
editing file or from a parent dir. If there is no
such file then indenter starts to use file from a dir
with the name current CodeStyle settings.
- Test fixed

ToDo: Add file absentness processing in case of import

Change-Id: If09ef0c598899856b948c214e524bcfd5dad76e2
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/clangformat/clangformatindenter.h

@@ -41,7 +41,6 @@ public:
 private:
     bool formatCodeInsteadOfIndent() const override;
     bool formatWhileTyping() const override;
-    clang::format::FormatStyle styleForFile() const override;
     int lastSaveRevision() const override;
 };