[tools] Commit memory debug (et al) tooling

These are some changes I made to debug tooling while tracking down the
bugfix in the previous commit.

Each `scripts/debug_*_alloc.gdb` script has gdb output a `*_allocs.txt`
file, which in turn can be parsed by the `scripts/parse_*_allocs.py`
script to find errors.

.vscode/launch.json

@@ -18,7 +18,9 @@
             "stopAtConnect": true,
             "stopAtEntry": false,
 
-            "setupCommands": [],
+            "setupCommands": [
+                {"text": "dashboard -enabled off", "ignoreFailures": true}
+            ],
 
             "MIMode": "gdb",
             "miDebuggerServerAddress": "localhost:1234",