Merge branch 'ds/trace2-regions-in-tests'

The default setting for trace2 event nesting was too low to cause test failures, which is worked around by bumping it up in the test framework. * ds/trace2-regions-in-tests: t/t*: remove custom GIT_TRACE2_EVENT_NESTING test-lib.sh: set GIT_TRACE2_EVENT_NESTING