• Pass context to _get_default_module_async to provide template globals to imports.
• Added tests.
• Refactored existing and new import global tests to use existing fixtures.
• Copied CHANGES.rst entry from Fix bug with imported macros and template globals #1241 since it best described the fix.

Relevant issues and PRs:

• One-liner, relies on the fix in PR Fix bug with imported macros and template globals #1241
• fixes Template globals are not accessible within imports w/ enable_async #1494

Checklist:

• Add tests that demonstrate the correct behavior of the change. Tests should fail without the change.
• Add or update relevant docs, in the docs folder and in code.
• Add an entry in CHANGES.rst summarizing the change and linking to the issue.
• Add .. versionchanged:: entries in any relevant code docs.
• Run pre-commit hooks and fix any issues.
• Run pytest and tox, no tests failed.