Re-enabled tst_LargeFile

tst_LargeFile currently seems to pass in a stable way in CI

It does have an issue on 64-bit Linux (see QTBUG-21175), so
that test function is still disabled (QEXPECT_FAIL'ed) on that platform.

Change-Id: I818046f84f2db5eb2155ae1f51f69581029bfaee
Reviewed-by: Jason McDonald <jason.mcdonald@nokia.com>
Reviewed-by: Shane Kearns <shane.kearns@accenture.com>

tests/auto/corelib/io/qfile/largefile/largefile.pro

@@ -7,4 +7,3 @@ SOURCES += tst_largefile.cpp
 wince*: SOURCES += $$QT_SOURCE_TREE/src/corelib/kernel/qfunctions_wince.cpp
 
 CONFIG += parallel_test
-CONFIG += insignificant_test # QTBUG-21175

tests/auto/corelib/io/qfile/largefile/tst_largefile.cpp

@@ -521,6 +521,9 @@ void tst_LargeFile::mapOffsetOverflow()
         uchar *address = 0;
 
         address = largeFile.map(((qint64)1 << i), blockSize);
+#if defined(__x86_64__)
+        QEXPECT_FAIL("", "fails on 64-bit Linux (QTBUG-21175)", Abort);
+#endif
         QVERIFY( !address );
 
         address = largeFile.map(((qint64)1 << i) + blockSize, blockSize);