nose: clean up, support Python 3.10. (#8825)

Due to changes in setuptools, we need to run 2to3 ourselves.
While we're at it, lets apply relevant patches from Debian.

https://salsa.debian.org/python-team/packages/nose/

dev-python/nose/patches/debian/coverage4.1.diff

@@ -0,0 +1,44 @@
+From: Dmitry Shachnev <mitya57@gmail.com>
+Date: Wed, 29 Jun 2016 13:15:16 +0300
+Subject: Make coverage plugin compatible with Coverage.py 4.1
+
+According to the Coverage.py 4.1 changelog:
+
+- The `Coverage.report` function had two parameters with non-None defaults,
+  which have been changed.  `show_missing` used to default to True, but now
+  defaults to None.  If you had been calling `Coverage.report` without
+  specifying `show_missing`, you'll need to explicitly set it to True to keep
+  the same behavior.
+
+Without that option, four tests in nose fail:
+
+- test_coverage_plugin.TestCoverageMinPercentagePlugin
+- test_coverage_plugin.TestCoverageMinPercentageSinglePackagePlugin
+- test_coverage_plugin.TestCoverageMinPercentageSinglePackageWithBranchesPlugin
+- test_coverage_plugin.TestCoveragePlugin
+---
+ nose/plugins/cover.py | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/nose/plugins/cover.py b/nose/plugins/cover.py
+index fbe2e30..b9bfc82 100644
+--- a/nose/plugins/cover.py
++++ b/nose/plugins/cover.py
+@@ -187,7 +187,7 @@ class Coverage(Plugin):
+                     for name, module in sys.modules.items()
+                     if self.wantModuleCoverage(name, module)]
+         log.debug("Coverage report will cover modules: %s", modules)
+-        self.coverInstance.report(modules, file=stream)
++        self.coverInstance.report(modules, file=stream, show_missing=True)
+ 
+         import coverage
+         if self.coverHtmlDir:
+@@ -207,7 +207,7 @@ class Coverage(Plugin):
+         # make sure we have minimum required coverage
+         if self.coverMinPercentage:
+             f = StringIO.StringIO()
+-            self.coverInstance.report(modules, file=f)
++            self.coverInstance.report(modules, file=f, show_missing=True)
+ 
+             multiPackageRe = (r'-------\s\w+\s+\d+\s+\d+(?:\s+\d+\s+\d+)?'
+                               r'\s+(\d+)%\s+\d*\s{0,1}$')