Remove redundant QDir::fromNativeSeparators() call

QFileSystemEntry::QFileSystemEntry(const QString &filePath) already
calls this function. Calling it repeatedly changes nothing but wastes
CPU time. Neither the line modified in this commit nor the
QFileSystemEntry's constructor have been changed since 2011's commit
"Initial import from the monolithic Qt." Other constructor overloads of
QFileInfoPrivate don't call QDir::fromNativeSeparators().

Change-Id: I01e54662efd96e87c4a686369dc0b265b47e5938
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/io/qfileinfo_p.h

@@ -101,7 +101,7 @@ public:
         cache_enabled(copy.cache_enabled), fileFlags(0), fileSize(0)
     {}
     inline QFileInfoPrivate(const QString &file)
-        : fileEntry(QDir::fromNativeSeparators(file)),
+        : fileEntry(file),
         fileEngine(QFileSystemEngine::resolveEntryAndCreateLegacyEngine(fileEntry, metaData)),
         cachedFlags(0),
 #ifndef QT_NO_FSFILEENGINE