Revert "Merge the ProgramBinary class into Program."

Issues appeared on the FYI waterfall, content_gl_tests hangs.

This reverts commit 2195a6d6032883ed05468d5ecd019e7cb9a27bce.

Change-Id: I9fe1a53cf40887ae5a98fd77b4872f41085fcea7
Reviewed-on: https://chromium-review.googlesource.com/232386
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>