Remove the old _find_dom_spot tests

This set of tests got left over from the great renaming.

tests/test_dom_spot.py

@@ -1,39 +0,0 @@
-import pytest
-
-from textual.widget import Widget
-from textual.dom import DOMError
-
-class Content(Widget):
-    pass
-
-class Body(Widget):
-    pass
-
-def test_find_dom_spot():
-
-    # Build up a "fake" DOM for an application.
-    screen = Widget(name="Screen")
-    header = Widget(name="Header", id="header")
-    body   = Body(id="body")
-    content = [ Content(id=f"item{n}") for n in range(1000)]
-    body._add_children(*content)
-    footer = Widget(name="Footer", id="footer")
-    screen._add_children(header, body, footer)
-
-    # Just as a quick double-check, make sure the main components are in
-    # their intended place.
-    assert list(screen.children) == [header,body,footer]
-
-    # Now check that we find what we're looking for in the places we expect
-    # to find them.
-    assert screen._find_spot(None) == (screen,-1)
-    assert screen._find_spot(1) == (screen, 1)
-    assert screen._find_spot(body) == screen._find_spot(1)
-    assert screen._find_spot("Body") == screen._find_spot(body)
-    assert screen._find_spot("#body") == screen._find_spot(1)
-
-    # Finally, let's be sure that we get an error if, for some odd reason,
-    # we go looking for a widget that isn't actually part of the DOM we're
-    # looking in.
-    with pytest.raises(DOMError):
-        _ = screen._find_spot(Widget())