gh-107510: gettext: Remove unnecessary tests

[tomasr8]

More discussion: #107510 (comment)

(It wouldn't let me reopen the original PR so I'm opening a new one)

Now that we have a decent amount of tests for pygettext, it's a good time to remove these tests.

• Issue: gettext: remove unecessary test cases testing single/double quotes #107510

[serhiy-storchaka]

LGTM. 👍

[tomasr8]

Thanks Serhiy!

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 CentOS9 NoGIL Refleaks 3.x has failed when building commit 0f20281.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/1610/builds/855) and take a look at the build logs.
4. Check if the failure is related to this commit (0f20281) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/1610/builds/855

Failed tests:

• test_free_threading

Summary of the results of the build (if available):

==

Click to see traceback logs

remote: Enumerating objects: 9, done.        
remote: Counting objects:  11% (1/9)        
remote: Counting objects:  22% (2/9)        
remote: Counting objects:  33% (3/9)        
remote: Counting objects:  44% (4/9)        
remote: Counting objects:  55% (5/9)        
remote: Counting objects:  66% (6/9)        
remote: Counting objects:  77% (7/9)        
remote: Counting objects:  88% (8/9)        
remote: Counting objects: 100% (9/9)        
remote: Counting objects: 100% (9/9), done.        
remote: Compressing objects:  50% (1/2)        
remote: Compressing objects: 100% (2/2)        
remote: Compressing objects: 100% (2/2), done.        
remote: Total 5 (delta 4), reused 3 (delta 3), pack-reused 0 (from 0)        
From https://github.com/python/cpython
 * branch                    main       -> FETCH_HEAD
Note: switching to '0f20281fa2f39673ec5d4a562e00d2f413890066'.

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Turn off this advice by setting config variable advice.detachedHead to false

HEAD is now at 0f20281fa2f gh-107510: gettext: Remove unnecessary tests (GH-127965)
Switched to and reset branch 'main'

configure: WARNING: no system libmpdecimal found; falling back to bundled libmpdecimal (deprecated and scheduled for removal in Python 3.15)

make: *** [Makefile:2325: buildbottest] Error 2