test: improve test coverage of internal/blob
This improves a test coverage in lib/internal/blob
ref: https://coverage.nodejs.org/coverage-74b9baa4265a8f0d/lib/internal/blob.js.html
This added following tests.
- executing inspect to Blob with
depth
option - creating new Blob instance with over size argument
- causing
ERR_INVALID_THIS
errors in some methods