Revert "Add fix for tmux 2.1"

This reverts commit 0dace647f9.

tests/babi_test.py

@@ -1,5 +1,4 @@
 import contextlib
-import functools
 import io
 import shlex
 import sys
@@ -31,24 +30,10 @@ def test_get_lines(s, lines, nl, mixed):
     assert ret == (lines, nl, mixed)
 
 
-@functools.lru_cache(maxsize=1)
-def _tmux_height_off_by_one():
-    with Runner(sys.executable, '-c', 'input(">")', height=24) as h:
-        h.await_text('>')
-        cmd = ('display', '-t0', '-p', '#{pane_height}')
-        height = int(h.tmux.execute_command(*cmd))
-        h.press('Enter')
-        h.await_exit()
-    assert height in (23, 24)
-    return height == 23
-
-
 class PrintsErrorRunner(Runner):
-    def __init__(self, *args, height=24, **kwargs):
+    def __init__(self, *args, **kwargs):
         self._screenshots: List[str] = []
-        if _tmux_height_off_by_one():  # pragma: no cover (tmux 2.1)
-            height += 1
-        super().__init__(*args, height=height, **kwargs)
+        super().__init__(*args, **kwargs)
 
     def screenshot(self, *args, **kwargs):
         ret = super().screenshot(*args, **kwargs)