testdata: strip unused fields from all test data files (23MB -> 4MB)

Strip fields not consumed by any test from all 594 HuJSON test data files:

grant_results/ (248 files, 21MB -> 1.8MB):
  - Remove: timestamp, propagation_wait_seconds, input.policy_file,
    input.grants_section, input.api_endpoint, input.api_method,
    topology.nodes.mts_name, topology.nodes.socket, topology.nodes.user_id,
    captures.commands, captures.packet_filter_matches, captures.whois
  - V14-V16, V26-V36: keep stripped netmap (Peers.Name/AllowedIPs/PrimaryRoutes
    + PacketFilterRules) for via_compat_test.go compatibility
  - V17-V25: strip netmap (old topology, incompatible with via_compat harness)

acl_results/ (215 files, 1.4MB -> 1.2MB):
  - Remove: timestamp, propagation_wait_seconds, input.policy_file,
    input.api_endpoint, input.api_response_code, entire topology section
    (parsed by Go struct but completely ignored — nodes are hardcoded)

routes_results/ (92 files, unchanged — topology is actively used):
  - Remove: timestamp, propagation_wait_seconds, input.policy_file,
    input.api_endpoint, input.api_response_code

ssh_results/ (39 files, unchanged — minimal to begin with):
  - Remove: policy_file

hscontrol/policy/v2/testdata/ssh_results/SSH-A7.hujson

@@ -5,7 +5,6 @@
 // Expected: SSH rules on 3 of 5 nodes
 {
   "test_id": "SSH-A7",
-  "policy_file": "ssh_policies/ssh_a7.json",
   "ssh_section": [
     {
       "action": "check",