optee-test_git.bb: add optee-test recipe & patches

This has moved from meta-linaro to meta-arm as this
is the new place for general recipes for Arm arch
and has a mailing list for external contributors.

python2 is now EOL. This patch updates to python3
but is a backport from v3.8.0 release.

Change-Id: Ib778b8dd9c605e1fbb69627f5e640c1683c3176b
Tested-by: Denys Dmytriyenko <denys@ti.com>
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>