analyzer: stash values for CPython plugin [PR107646]

analyzer: stash values for CPython plugin [PR107646]

This patch adds a hook to the end of ana::on_finish_translation_unit
which calls relevant stashing-related callbacks registered during plugin
initialization. This feature is used to stash named types and global
variables for a CPython analyzer plugin [PR107646].

gcc/analyzer/ChangeLog:
	PR analyzer/107646
	* analyzer-language.cc (run_callbacks): New function.
	(on_finish_translation_unit): New function.
	* analyzer-language.h (GCC_ANALYZER_LANGUAGE_H): New include.
	(class translation_unit): New vfuncs.

gcc/c/ChangeLog:
	PR analyzer/107646
	* c-parser.cc: New functions on stashing values for the
	analyzer.

gcc/testsuite/ChangeLog:
	PR analyzer/107646
	* gcc.dg/plugin/plugin.exp: Add new plugin and test.
	* gcc.dg/plugin/analyzer_cpython_plugin.c: New plugin.
	* gcc.dg/plugin/cpython-plugin-test-1.c: New test.

Signed-off-by: Eric Feng <ef2648@columbia.edu>