Verifies that inserting a paragraph before a space does not cause text after the insertion position to be deleted.

Before inserting paragraph:
| "\n    "
| <p>
|   "Hello<#selection-caret> world"
| "\n\n\n"

After inserting paragraph:
| "\n    "
| <p>
|   "Hello"
| <p>
|   "<#selection-caret> world"
| "\n\n\n"