bpo-36876: Re-organize the c-analyzer tool code. (gh-16841)

This is partly a cleanup of the code. It also is preparation for getting the variables from the source (cross-platform) rather than from the symbols.

The change only touches the tool (and its tests).

Author: ericsnowcurrently

Diff for: Lib/test/test_check_c_globals.py

@@ -3,7 +3,7 @@
 
 test.test_tools.skip_if_missing('c-analyzer')
 with test.test_tools.imports_under_tool('c-analyzer'):
-    from c_globals.__main__ import main
+    from cpython.__main__ import main
 
 
 class ActualChecks(unittest.TestCase):