[libc++][Android] Avoid triggering fdsan in filebuf test

[rprichard]

Summary

The fd is opened by std::filebuf, which uses stdio (FILE*). Attempting
to close the fd directly with close() would trigger fdsan.

libcxx/test/std/input.output/file.streams/fstreams/filebuf.members/close.pass.cpp

#if defined(__unix__)
         std::filebuf f;
         assert(!f.is_open());
         // Use open directly to get the file descriptor.
         int fd = open(temp.c_str(), O_RDWR);
         assert(fd >= 0);
         // Use the internal method to create filebuf from the file descriptor.
         assert(f.__open(fd, std::ios_base::out) != 0);
         assert(f.is_open());
+
+        // With Bionic, fdsan aborts the process when close() is called on an fd
+        // belonging to a FILE*, so disable this part of the test. See
+        // https://github.com/android/ndk/issues/1626.
+#if !defined(__BIONIC__)
         // Close the file descriptor directly to force filebuf::close to fail.
         assert(close(fd) == 0);
         // Ensure that filebuf::close handles the failure.
         assert(f.close() == nullptr);
         assert(!f.is_open());
         assert(f.close() == nullptr);
+#endif
     }
 #endif
     std::remove(temp.c_str());
 
     return 0;
 }