servo: Merge #19855 - Added --progress flag to test-perf git commands (from asajeffrey:test-perf-git-progress); r=jdm

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Adding a `--progress` flag to git commands in test-perf to try to avoid the timeouts we're seeing at http://build.servo.org/builders/linux-nightly/builds/581/steps/test/logs/stdio
---
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes do not require tests because this is test infrastructure

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Source-Repo: https://github.com/servo/servo
Source-Revision: 8c1af9cce7197104dda76873be6c713e0b0d3866

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : 7a1d217d458222e072c59547947912a519e028d5

servo/etc/ci/performance/test_perf.sh

@@ -31,11 +31,11 @@ WARC_REPO="git@github.com:servo/servo-warc-tests.git"
 
 # Clone the warc tests if they don't exist
 if [[ ! -d ${WARC_DIR} ]]; then
-    git clone ${WARC_REPO}
+    git clone --progress ${WARC_REPO}
 fi
 
 # Make sure we're running with an up-to-date warc test repo
-git -C ${WARC_DIR} pull
+git -C ${WARC_DIR} pull --progress
 
 virtualenv venv --python="$(which python3)"
 PS1="" source venv/bin/activate