Change the limit on the input size for b2a_base64 to what will fit in memory, rather than the standard's 57.
Change the limit on the input size for b2a_base64 to what will fit in
memory, rather than the standard's 57.

This fixes SF bug #473009.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator