[mozcrash] Copy minidumps files instead of moving to avoid failures i…

…n case files already exist.

Differential Revision: https://phabricator.services.mozilla.com/D230493

bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1882338
gecko-commit: 0d66f48f5e4312b222f6cdbb6e8a8fb0f7481e16
gecko-reviewers: webdriver-reviewers, whimboo, jmaher

tools/wptrunner/requirements_firefox.txt

@@ -1,5 +1,5 @@
 marionette_driver==3.4.0
-mozcrash==2.2.0
+mozcrash==2.2.1
 mozdevice==4.2.0
 mozinstall==2.1.0
 mozleak==0.2