Add branch coverage to our coveralls run

Add branch coverage to our coveralls run

Coveralls is capable of reporting not only covered lines in a build, but
also the number of times a given branch was taken vs. not taken.  This
will help us identify locations where we might make better use of the
openssl_likely and openssl_unlikely macros to optimize branch prediction
when building openssl

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <ppzgs1@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/27839)