[3.10] pythongh-130293: Ensure test__colorize will pass on dumb terminals. (pythonGH-130333) (python#130334)

Ensure colorize tests will run on dumb terminals (or environment with TERM=dumb set)

(cherry picked from commit 1b07006)

Co-authored-by: Russell Keith-Magee <russell@keith-magee.com>

Author: miss-islington

Misc/NEWS.d/next/Tests/2025-02-20-13-39-12.gh-issue-130293.5igSsu.rst

@@ -0,0 +1,2 @@
+The tests of terminal colorization are no longer sensitive to the value of
+the ``TERM`` variable in the testing environment.

iOS/testbed/iOSTestbedTests/iOSTestbedTests.m

@@ -28,7 +28,7 @@ - (void)testPython {
     // Xcode log can't display color. Stdout will report that it is *not* a
     // TTY.
     setenv("NO_COLOR", "1", true);
-    setenv("PY_COLORS", "0", true);
+    setenv("PYTHON_COLORS", "0", true);
 
     // Arguments to pass into the test suite runner.
     // argv[0] must identify the process; any subsequent arg