[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/parse_frame_allocs.py

@@ -0,0 +1,40 @@
+#!/usr/bin/env python3
+
+def add_maps(allocs, addr, count):
+    for i in range(count):
+        if addr+i in allocs:
+            print(f"ERROR: frame {addr+i:012x} map collision.")
+        else:
+            #print(f"       frame {addr+i:012x} mapped")
+            allocs.add(addr+i)
+
+def remove_maps(allocs, addr, count):
+    for i in range(count):
+        if addr+i not in allocs:
+            print(f" WARN: removing unmapped frame {addr+i:012x}")
+        else:
+            #print(f"       frame {addr+i:012x} unmapped")
+            allocs.remove(addr+i)
+
+def parse_line(allocs, line):
+    args = line.strip().split()
+    match args:
+        case ['+', addr, count]:
+            add_maps(allocs, int(addr, base=16), int(count))
+        case ['-', addr, count]:
+            remove_maps(allocs, int(addr, base=16), int(count))
+        case _:
+            pass
+
+def parse_file(f):
+    allocs = set()
+    for line in f.readlines():
+        parse_line(allocs, line)
+
+if __name__ == "__main__":
+    import sys
+    if len(sys.argv) > 1:
+        with open(sys.argv[1]) as f:
+            parse_file(f)
+    else:
+        parse_file(sys.stdin)