Fix warning from testing assignment

Tests that do

QTRY_VERIFY(a = b);

generate a compiler warning:

using the result of an assignment as a condition without parentheses
[-Wparentheses]: place parentheses around the assignment to silence
this warning

Do that centrally in the QTRY_TIMEOUT_DEBUG_IMPL macro definition.

Pick-to: 6.4
Change-Id: I4a4b0161c4e16c0e1e27a68f33a41efdaa2c962c
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/testlib/qtestcase.h

@@ -168,7 +168,7 @@ inline void useVerifyThrowsException() {}
 #define QTRY_TIMEOUT_DEBUG_IMPL(expr, timeoutValue, step) \
     if (!QTest::currentTestFailed() && !(expr)) { \
         QTRY_LOOP_IMPL(expr, 2 * (timeoutValue), step) \
-        if (expr) { \
+        if ((expr)) { \
             QFAIL(qPrintable(QTest::Internal::formatTryTimeoutDebugMessage(\
                                  u8"" #expr, timeoutValue, timeoutValue + qt_test_i))); \
         } \