Silence GCC 8 warning on memcpy of movable types

This is similar to commit 342bb5b03a.

From GCC 8:

qarraydataops.h:84:17: error: ‘void* memcpy(void*, const void*, size_t)’ writing to an object of type ‘class QStringRef’ with no trivial copy-assignment; use copy-assignment or copy-initialization instead [-Werror=class-memaccess]
[etc.]

Change-Id: I41d006aac5bc48529845fffd150e817e64973bec
Reviewed-by: Ville Voutilainen <ville.voutilainen@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/tools/qarraydataops.h

@@ -76,7 +76,8 @@ struct QPodArrayOps
         Q_ASSERT(b < e);
         Q_ASSERT(size_t(e - b) <= this->alloc - uint(this->size));
 
-        ::memcpy(this->end(), b, (e - b) * sizeof(T));
+        ::memcpy(static_cast<void *>(this->end()), static_cast<const void *>(b),
+                 (e - b) * sizeof(T));
         this->size += e - b;
     }
 

src/corelib/tools/qvarlengtharray.h

@@ -344,7 +344,7 @@ Q_OUTOFLINE_TEMPLATE void QVarLengthArray<T, Prealloc>::append(const T *abuf, in
         while (s < asize)
             new (ptr+(s++)) T(*abuf++);
     } else {
-        memcpy(&ptr[s], abuf, increment * sizeof(T));
+        memcpy(static_cast<void *>(&ptr[s]), static_cast<const void *>(abuf), increment * sizeof(T));
         s = asize;
     }
 }
@@ -392,7 +392,7 @@ Q_OUTOFLINE_TEMPLATE void QVarLengthArray<T, Prealloc>::realloc(int asize, int a
                 QT_RETHROW;
             }
         } else {
-            memcpy(ptr, oldPtr, copySize * sizeof(T));
+            memcpy(static_cast<void *>(ptr), static_cast<const void *>(oldPtr), copySize * sizeof(T));
         }
     }
     s = copySize;