bpo-35196: Optimize Squeezer's write() interception (GH-10454)

The new functionality of Squeezer.reload() is also tested, along with some general
re-working of the tests in test_squeezer.py.

Author: taleinat

Lib/idlelib/NEWS.txt

@@ -3,6 +3,8 @@ Released on 2019-10-20?
 ======================================
 
 
+bpo-35196: Speed up squeezer line counting.
+
 bpo-35208: Squeezer now counts wrapped lines before newlines.
 
 bpo-35555: Gray out Code Context menu entry when it's not applicable.

Lib/idlelib/editor.py

@@ -317,9 +317,6 @@ def __init__(self, flist=None, filename=None, key=None, root=None):
         text.bind("<<zoom-height>>", self.ZoomHeight(self).zoom_height_event)
         text.bind("<<toggle-code-context>>",
                   self.CodeContext(self).toggle_code_context_event)
-        squeezer = self.Squeezer(self)
-        text.bind("<<squeeze-current-text>>",
-                  squeezer.squeeze_current_text_event)
 
     def _filename_to_unicode(self, filename):
         """Return filename as BMP unicode so diplayable in Tk."""