Difference in Ctrl+D Behavior Between REPL and `code.interact`

Bug report

Bug description:

With #133883 merged, hitting ctrl+d at the start of a blank line in a multi-line entry causes the existing code to be evaluated in both the new REPL and the basic REPL:

>>> def foo(x):
... 
  File "<python-input-0>", line 1
    def foo(x):
               ^
IndentationError: expected an indented block after function definition on line 1

But code.interact() exits immediately without executing the existing code:

>>> def foo(x):
... 

now exiting InteractiveConsole...

I doubt this is terribly impactful, but I think it would still be nice to have these behave the same way.

I have a patch ready that I think will resolve this, so I'll open a PR shortly.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-139876

Start by comparing Ctrl+D handling in the new and basic REPL with code.interact(), using the blank-line multi-line function definition reproduction in the issue. Done means code.interact() evaluates the existing code consistently with the other REPLs; linked PR gh-139876 indicates work is already underway.