Utils: Introduce FilePath::isSameExecutable()

... to replace Environment::isSameExectuable().

New code is a filepathified copy of the orginal.

Change-Id: Iebf61cd183c9a5c03a5b8a90a33b5e074af9ecbe
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>
Reviewed-by: hjk <hjk@qt.io>

src/libs/utils/filepath.h

@@ -210,6 +210,7 @@ public:
 
     bool isSameDevice(const FilePath &other) const;
     bool isSameFile(const FilePath &other) const;
+    bool isSameExecutable(const FilePath &other) const; // with potentially different suffixes
 
     [[nodiscard]] QFileInfo toFileInfo() const;
     [[nodiscard]] static FilePath fromFileInfo(const QFileInfo &info);