[PATCH] tests: remove sys.executable from "required tools"

[Augie Fackler]

# HG changeset patch
# User Augie Fackler <raf at durin42.com>
# Date 1496021613 14400
#      Sun May 28 21:33:33 2017 -0400
# Node ID 653af0af46f7f9d46000185f1039d49fb6ffc275
# Parent  3ef319e9505f376775c91b2ab7d89ac9ac4343e9
tests: remove sys.executable from "required tools"

In practice this doesn't appear to have been true for some time - we
reference Python using the $PYTHON variable in all the tests now
(which we have to for PyPy and Python 3), and I've been using
~/.../python.exe to test with tip of the cpython 3.6 release branch
while working on manifest tests in Python 3 and everything seems to be
just fine. The only real observable difference from this change is
that I stop getting a warning about python.exe not being a thing on
$PATH, which seems like an improvement.

diff --git a/tests/run-tests.py b/tests/run-tests.py
--- a/tests/run-tests.py
+++ b/tests/run-tests.py
@@ -2063,7 +2063,6 @@ class TestRunner(object):
 
     # Programs required to run tests.
     REQUIREDTOOLS = [
-        os.path.basename(_bytespath(sys.executable)),
         b'diff',
         b'grep',
         b'unzip',