`match` hook with `block` + false `if` should set empty map

[robcxyz]

In a match hook, when there is a matched block with a false if condition, the return should be an empty map. Right now iin this example we don't set any key (ie matches_false does not exist.

matcher: block_true
# This should exist in output as empty key
matches_false:
  ->: match matcher
  case:
    # This key should not exist
    block_true->:
      if: false
      value: True

Results in

matcher: bock_true

Which should be empty or an error (ie the matched key does not exist).

matcher: 

Super edge case so low priority.