QSharedMemoryLocker: add missing move SMFs and member- and ADL swap

This fixes clazy-rule-of-three (and -Wpeppe). The actual operations
performed are copied from QMutexLocker.

This code predates the public history.

Pick-to: 6.7
Change-Id: Ieba73502187b32178ec2601e1902ac6b20a8e477
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
(cherry picked from commit a6f1779207958f25abeaa39b03d6459586bc7575)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/corelib/ipc/qsharedmemory_p.h

@@ -41,13 +41,22 @@ class QSharedMemoryPrivate;
   */
 class QSharedMemoryLocker
 {
-
+    Q_DISABLE_COPY(QSharedMemoryLocker)
 public:
     Q_NODISCARD_CTOR QSharedMemoryLocker(QSharedMemory *sharedMemory) : q_sm(sharedMemory)
     {
         Q_ASSERT(q_sm);
     }
 
+    Q_NODISCARD_CTOR QSharedMemoryLocker(QSharedMemoryLocker &&other) noexcept
+        : q_sm{std::exchange(other.q_sm, nullptr)}
+    {}
+
+    QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_MOVE_AND_SWAP(QSharedMemoryLocker)
+
+    void swap(QSharedMemoryLocker &other) noexcept
+    { qt_ptr_swap(q_sm, other.q_sm); }
+
     inline ~QSharedMemoryLocker()
     {
         if (q_sm)
@@ -63,6 +72,9 @@ public:
     }
 
 private:
+    friend void swap(QSharedMemoryLocker &lhs, QSharedMemoryLocker &rhs) noexcept
+    { lhs.swap(rhs); }
+
     QSharedMemory *q_sm;
 };
 #endif // QT_CONFIG(systemsemaphore)