Remove empty alternative service vector from |alternative_service_map_|.
Remove empty alternative service vector from |alternative_service_map_| in
HttpServerPropertiesImpl::GetAlternativeServices().
The reporter of the bug confirmed that Patch Set 1 fixes the crash on their
local build.
The author of this CL confirmed that the regression test added in Patch Set 2
run without the fix in Patch Set 1 does crash on a local build.
Note that this is only half of the bug: the same problem still persists for
canonical hosts. That deserves another regression test and another CL.
BUG=516486
Review URL: https://codereview.chromium.org/
1256113005
Cr-Commit-Position: refs/heads/master@{#341708}