[gdb] Drop gdb.stabs exclude from tclint.toml

Now that gdb/testsuite/gdb.stabs has been removed, drop the corresponding
exclude from gdb/tclint.toml.

Tested by running "pre-commit run --all-files".

gdb/tclint.toml

diff --git a/gdb/tclint.toml b/gdb/tclint.toml
index 92b8d3d..2a39491 100644
--- a/gdb/tclint.toml
+++ b/gdb/tclint.toml
@@ -34,7 +34,6 @@
 "gdb/testsuite/boards",
 "gdb/testsuite/config",
 # IGNORE (document reason in trailing comment):
-"gdb/testsuite/gdb.stabs", # To be removed.
 "gdb/testsuite/lib/ton.tcl", # Imported.
 ]