[beta] Remove allocation from width of character function.

[XAMPPRocky]

Backport of #48167

r? @Mark-Simulacrum

[rust-highfive]

Warning

• Pull requests are usually filed against the master branch for this repo, but this one is against beta. Please double check that you specified the right target!

[kennytm]

@bors r+ p=2

[bors]

📌 Commit 926c5cc has been approved by kennytm

[bors]

⌛ Testing commit 926c5cc with merge ac3e34e...

[bors]

💔 Test failed - status-travis

[kennytm]

@bors retry

dist-i686-freebsd 3 hour timeout, everything built but not enough time to deploy.

[02:56:26] Build completed successfully in 2:51:45

travis_time:end:08c8e912:start=1520176741402953472,finish=1520187328536791573,duration=10587133838101

The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 0.
travis_time:start:0a20c790
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)

Sun Mar  4 18:15:28 UTC 2018
Sun, 04 Mar 2018 18:15:28 GMT


travis_time:end:0a20c790:start=1520187328562174678,finish=1520187328629579199,duration=67404521

The command "date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)
" exited with 0.
travis_fold:start:before_cache
travis_time:start:001692f0
$ docker history -q rust-ci | grep -v missing | xargs docker save | gzip > $HOME/docker/rust-ci.tar.gz

travis_time:end:001692f0:start=1520187328640774170,finish=1520187376617325941,duration=47976551771
travis_fold:end:before_cache
travis_fold:start:cache.2
store build cache
travis_time:start:00e42abc

travis_time:end:00e42abc:start=1520187376630229082,finish=1520187376641277006,duration=11047924
travis_time:start:068ff610
change detected (content changed, file is created, or file is deleted):
/home/travis/docker/rust-ci.tar.gz


changes detected, packing new archive


The job exceeded the maximum time limit for jobs, and has been terminated.

[bors]

⌛ Testing commit 926c5cc with merge e93f6e0...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: kennytm
Pushing e93f6e0 to beta...