Build log truncation is currently silent and can easily go unnoticed
unless you notice missing expected output (such as a filename line
following a function name in a stack trace).
Adjust livelog to explicitly annotate truncation at the end of a log so
that it is very clear to readers.
Fixesgolang/go#45972
Change-Id: I5ad555232ba670bfb37d2eb3d2260307468c28a9
Reviewed-on: https://go-review.googlesource.com/c/build/+/317209
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>