Restore decimal context after decimal doctests

The modified context caused tests failures in several other tests.

Author: serhiy-storchaka

Lib/test/test_decimal.py

@@ -5892,13 +5892,16 @@ def load_tests(loader, tests, pattern):
 
     if TODO_TESTS is None:
         from doctest import DocTestSuite, IGNORE_EXCEPTION_DETAIL
+        orig_context = orig_sys_decimal.getcontext().copy()
         for mod in C, P:
             if not mod:
                 continue
             def setUp(slf, mod=mod):
                 sys.modules['decimal'] = mod
             def tearDown(slf):
                 sys.modules['decimal'] = orig_sys_decimal
+                mod.setcontext(ORIGINAL_CONTEXT[mod])
+                orig_sys_decimal.setcontext(orig_context)
             optionflags = IGNORE_EXCEPTION_DETAIL if mod is C else 0
             sys.modules['decimal'] = mod
             tests.addTest(DocTestSuite(mod, setUp=setUp, tearDown=tearDown,