Never truncate logs starting with #<number>

For locally debugging gtests, we sometimes add a log to output a stack
trace. Before this change, the stack trace was not shown because
gtest_test_instance.py treats the lines starting with #\d+ the stack
trace gtest itself emits on crash and extracts them. It causes confusion
for the local debugging scenario, and worse, when the symbolization
fails, the stack traces just vanish.

This change makes the log always shown fully, without getting the #\d+
lines removed, addressing the confusion the said false positives cause.

Bug: 407461474
Fixed: 407461474
Change-Id: I2341ef581d01f07ad80296d7ca15e4ce6d5a090d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6415349
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Keigo Oka <oka@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1441918}