MFC r298311,r298312:

r298311:

Make sure fmemopen succeeds in :test_append_binary_pos before calling ftell
on the FILE object

This fixes potential null pointer dereferences on failure

CID: 1254952

r298312:

Fix double fclose of fp1 when freopen fails

freopen handles closing file descriptors on error, with the exception of
fdopen'ed descriptors, so closing an already fclose'd file descriptor is
incorrect

CID: 1338525