This removes error messages about missing _True labels, and instead tries
find overloads for the branch protocol and a normal function call at the
same time. The branch protocol is only considered if there are _True and
_False in the context and the overload returns never.
In addition, it prints all macro names of operator overloads if none
was matching.


Bug: v8:7793
Change-Id: Id81712f5b7f2af6765e23bb1f37438f141a79316
Reviewed-on: https://chromium-review.googlesource.com/1109839Reviewed-by: Daniel Clifford <danno@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53943}