[3.12] Remove imp_dummy_def from Tools/c-analyzer/cpython/ignored.tsv (gh-112122) (gh-112177)

It was removed in 3.12, no need to keep the ignore.
(cherry picked from commit 762eb58)

Co-authored-by: Nikita Sobolev <[email protected]>

Author: miss-islington

Tools/c-analyzer/cpython/ignored.tsv

@@ -550,7 +550,6 @@ Modules/_testmultiphase.c	-	def_nonascii_latin	-
 Modules/_testmultiphase.c	-	def_nonmodule	-
 Modules/_testmultiphase.c	-	def_nonmodule_with_exec_slots	-
 Modules/_testmultiphase.c	-	def_nonmodule_with_methods	-
-Modules/_testmultiphase.c	-	imp_dummy_def	-
 Modules/_testmultiphase.c	-	main_def	-
 Modules/_testmultiphase.c	-	main_slots	-
 Modules/_testmultiphase.c	-	meth_state_access_slots	-