Using Envoy XDS TTL causes envoy to crash

(Already triaged by the security and ok to open an issue).

*Title*: *Using Envoy XDS TTL causes envoy to crash*

*Description*:
Hi,
I was just playing around to get an idea of what’s possible with XDSTTL. My config, in all recent versions (1.23->1.25), crashes Envoy when a ttl is reached (apparently). Though I only have the stack for 1.25 (full log attached).

Caught Segmentation fault, suspect faulting address 0x0
Backtrace (use tools/stack_decode.py to get line numbers):
Envoy version: d362e791eb9e4efa8d87f6d878740e72dc8330ac/1.18.2/clean-getenvoy-76c310e-envoy/RELEASE/BoringSSL
#0: __restore_rt [0x7f1e64aea420]->[0x29700fe2d420] ??:0
#1: std::__1::__function::__func<>::operator()() [0x55ae568e53bd]->[0x1c283bd] ??:?
#2: event_process_active_single_queue [0x55ae56c085b7]->[0x1f4b5b7] snapshot.cc:?
#3: event_base_loop [0x55ae56c0720e]->[0x1f4a20e] snapshot.cc:?
#4: Envoy::Server::InstanceImpl::run() [0x55ae5653d7e8]->[0x18807e8] ??:?
#5: Envoy::MainCommonBase::run() [0x55ae54cbe9c4]->[0x19c4] ??:0
#6: Envoy::MainCommon::main() [0x55ae54cbf2e6]->[0x22e6] ??:0
#7: main [0x55ae54cbd13c]->[0x13c] ??:0
#8: __libc_start_main [0x7f1e64908083]->[0x29700fc4b083] ??:0

The test harness is nothing special, though I do presume there’s user error in my usage of ttl.….but it shouldn’t be crashing. I’m just using the go control plane and setting the ResourceWithTTL with static ttls for the test:
https://github.com/bladedancer/xds-test/blob/ttl/pkg/xds/worker.go#L164

[log.txt](https://github.com/envoyproxy/envoy/files/10125378/log.txt)