Detect allocation failures and bail gracefully

During the processing of several sample table related MP4 atoms, allocation
sizes could be large enough cause a std::bad_alloc exception to be raised. This
typically causes a crash (denial of service condition). Use std::nothrow to
catch allocation failures and return gracefully.

Bug: 20139950
Change-Id: I03d3f01b24e5fe3fa38985914bcfa694ea3dc09e