QByteArrayLiteral: Remove const temporary that may prevent optimization

clang-tidy 10 was complaining about
http://clang.llvm.org/extra/clang-tidy/checks/performance-no-automatic-move.html

Pick-To: 5.15
Change-Id: I63ba4111e01bb9d3ee87940253c4a79cc42c0bdf
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/text/qbytearray.h

@@ -125,8 +125,7 @@ using QByteArrayData = QArrayDataPointer<char>;
             static_cast<QTypedArrayData<char> *>(const_cast<QArrayData *>(&qbytearray_literal)), \
             const_cast<char *>(str), \
             Size }; \
-        const QByteArray ba(holder); \
-        return ba; \
+        return QByteArray(holder); \
     }()) \
     /**/