[SPARK-12712] Fix failure in ./dev/test-dependencies when run against empty .m2 cache
[SPARK-12712] Fix failure in ./dev/test-dependencies when run against empty .m2 cache

This patch fixes a bug in `./dev/test-dependencies.sh` which caused spurious failures when the script was run on a machine with an empty `.m2` cache. The problem was that extra log output from the dependency download was conflicting with the grep / regex used to identify the classpath in the Maven output. This patch fixes this issue by adjusting the regex pattern.

Tested manually with the following reproduction of the bug:

```
rm -rf ~/.m2/repository/org/apache/commons/
./dev/test-dependencies.sh
```

Author: Josh Rosen <e5dd8a3899598b2e85930c5ff06b11c053ef654f@databricks.com>

Closes #13568 from JoshRosen/SPARK-12712.

(cherry picked from commit 921fa40b14082bfd1094fa49fb3b0c46a79c1aaa)
Signed-off-by: Josh Rosen <e5dd8a3899598b2e85930c5ff06b11c053ef654f@databricks.com>

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