Revert "subprocess: Rename exception variables"

This reverts commit 3af56b2573a9bab49c6cfbae7bdf675cbc3c1bb8.
Add CPython shutil + tests
shutil: Get rid of conditional imports
Update pwd stubs
shutil: Refactor 'del' of local variable
Add callable to builtins stubs
shutil: Refactor local redefined as function
Add minimal distutils stubs
Add miminal grp stubs
Add empty bz2 stubs
Add empty tarfile stubs
Add empty zipfile stubs
shutil: Fix conditional name scoping issue

Cannot have a name conditionally defined in different scopes.
shutil: Add 'any' type annotation
shutil: Fix name aliasing problem
test_shutil: Remove references to undefined names

Code used dummy names which resulted in semantic analysis errors.
Update distutils.spawn stubs
test.test_shutil: Remove redundant import

The same name was imported twice.
shutil: Refactor runtime module func redefinition

Use variables explicitly for functions redefined at runtime by test
cases.
test_shutil: Get rid of conditional imports

Make them unconditional for now.