Exclude _testclinic_depr.c.h from c-analyzer (GH-137086)

_testclinic.c mocks out PY_VERSION_HEX to 3.8 before including
_testclinic_depr.c.h to avoid the errors the preprocessor would
otherwise throw due to the deprecation feature it is testing.

Also partially revert 74e2acddf6:
this restores Modules/_testclinic.c to match the same file in the 3.14
branch.

Tools/c-analyzer/cpython/_parser.py

@@ -83,6 +83,8 @@ Python/frozen_modules/*.h
 Python/generated_cases.c.h
 Python/executor_cases.c.h
 Python/optimizer_cases.c.h
+# XXX: Throws errors if PY_VERSION_HEX is not mocked out
+Modules/clinic/_testclinic_depr.c.h
 
 # not actually source
 Python/bytecodes.c