Fix fstat_ut (#164)

libc 'open' (in implementation of TFile) doesn't create non-existed parent directories in given path, so we have to do that for it

Author: tsayukov

util/system/fstat_ut.cpp

@@ -105,6 +105,7 @@ Y_UNIT_TEST_SUITE(TestFileStat) {
 #endif
 
     Y_UNIT_TEST(SymlinkToExistingFileTest) {
+        NFs::MakeDirectory(GetOutputPath());
         const auto path = GetOutputPath() / "file_1";
         const auto link = GetOutputPath() / "symlink_1";
         TFile(path, EOpenModeFlag::CreateNew | EOpenModeFlag::RdWr);