[dev.boringcrypto] misc/boring: remove -trust and individual reviewers

[dev.boringcrypto] misc/boring: remove -trust and individual reviewers

The -trust flag has become obsolete.

A list of individual reviewers may become out of date, and these
scripts (and their backports) are probably not the optimal place
for it.

Change-Id: Ibf1bc508f0192b160c955e3deabae34f4d1ab54c
Reviewed-on: https://go-review.googlesource.com/c/go/+/399538
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>