[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.

scripts/debug_frame_alloc.gdb

@@ -0,0 +1,18 @@
+das -enabled off
+break frame_allocator.cpp:62
+commands
+silent
+printf "+ %016lx %3d\n", *address, n
+continue
+end
+break frame_allocator.cpp:95
+commands
+silent
+printf "- %016lx %3d\n", address, count
+continue
+end
+
+set logging file frame_allocs.txt
+set logging overwrite on
+set logging enabled on
+continue