test: enable crashtracking during all tests (#11282)

Explicitly enable the crashtracker during all tests.

We want to proactively find any new scenarios where the crash tracker
does not work, or causes issues with any other products/features.

## Checklist
- [x] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [ ] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
- Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

tests/conftest.py

@@ -27,6 +27,7 @@
 from ddtrace._trace.provider import _DD_CONTEXTVAR
 from ddtrace.internal.compat import httplib
 from ddtrace.internal.compat import parse
+from ddtrace.internal.core import crashtracking
 from ddtrace.internal.remoteconfig.client import RemoteConfigClient
 from ddtrace.internal.remoteconfig.worker import remoteconfig_poller
 from ddtrace.internal.runtime import get_runtime_id
@@ -113,6 +114,19 @@ def use_global_tracer():
     yield False
 
 
+@pytest.fixture
+def auto_enable_crashtracking():
+    yield True
+
+
+@pytest.fixture(autouse=True)
+def enable_crashtracking(auto_enable_crashtracking):
+    if auto_enable_crashtracking:
+        crashtracking.start()
+        assert crashtracking.is_started()
+    yield
+
+
 @pytest.fixture
 def tracer(use_global_tracer):
     if use_global_tracer: