[3.12] gh-111495: Add PyFile tests (#129449) (#129477) (#129501)

[3.13] gh-111495: Add PyFile tests (#129449) (#129477)

gh-111495: Add PyFile tests (#129449)

Add tests for the following functions in test_capi.test_file:

* PyFile_FromFd()
* PyFile_GetLine()
* PyFile_NewStdPrinter()
* PyFile_WriteObject()
* PyFile_WriteString()
* PyObject_AsFileDescriptor()

Remove test_embed.StdPrinterTests which became redundant.

(cherry picked from commit 4ca9fc08f89bf7172d41e523d9e520eb1729ee8c)
(cherry picked from commit 9a59a51733e58b6091ca9157fd43cc9d0f93a96f)