media-libs/tiff: revbump to address open security bugs

media-libs/tiff: revbump to address open security bugs

* This commit addresses 3 outstanding security issues reported by the
individuals listed below.

* This commit involved cherry-picking the patches and adding a revbump as
the original PR's renamed the original ebuild and kept stable keywords.

Bug: https://bugs.gentoo.org/639700
Bug: https://bugs.gentoo.org/690732

Closes: https://github.com/gentoo/gentoo/pull/12543
Closes: https://github.com/gentoo/gentoo/pull/11743

Reported-by: Benjamin Gordon <bmgordon@chromium.org>
Reported-by: Allen Webb <allenwebb@google.com>
Signed-off-by: Aaron Bauman <bman@gentoo.org>