QEventLoopLocker: use macro to implement move-ctor

We do have special macros for this case, so use one of them!

Amends c2956f8f76

Found in 6.7 API review.

Pick-to: 6.7
Change-Id: I205966d6f7363abf1a26f59b04555b1a48a4e696
Reviewed-by: Marc Mutz <marc.mutz@qt.io>

src/corelib/kernel/qeventloop.h

@@ -65,8 +65,7 @@ public:
 
     Q_NODISCARD_CTOR QEventLoopLocker(QEventLoopLocker &&other) noexcept
         : p{std::exchange(other.p, 0)} {}
-    QEventLoopLocker &operator=(QEventLoopLocker &&other) noexcept
-    { auto moved = std::move(other); swap(moved); return *this; }
+    QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_MOVE_AND_SWAP(QEventLoopLocker)
 
     void swap(QEventLoopLocker &other) noexcept { std::swap(p, other.p); }
     friend void swap(QEventLoopLocker &lhs, QEventLoopLocker &rhs) noexcept { lhs.swap(rhs); }