Intermittent crash in /html/dom/reflection-misc.html

[jdm]

Least useful crash stack:

 ▶ CRASH [expected OK] /html/dom/reflection-misc.html
  │ 
  │ Xlib:  extension "XFree86-VidModeExtension" missing on display ":0".
  │ Stack trace for thread "ScriptThread PipelineId { namespace_id: PipelineNamespaceId(0), index: PipelineIndex(0) }"
  │ stack backtrace:
  │    0:     0x7fc58c206b8d - backtrace::backtrace::trace::h0e60ef08c7c34e9f
  │    1:     0x7fc58c207212 - backtrace::capture::Backtrace::new::h8bf319c36d8f5d1b
  │    2:     0x7fc58a9dfa94 - servo::install_crash_handler::handler::h40399914f600372a
  │    3:     0x7fc58bb1e1b3 - AsmJSFaultHandler
  │                         at /home/servo/.cargo/git/checkouts/mozjs-fa11ffc7d4f1cc2d/master/mozjs/js/src/asmjs/WasmSignalHandlers.cpp:1171
  │    4:     0x7fc5888ff32f - <unknown>
  │    5:     0x7fc576b9a000 - <unknown>
  │ Stack trace for thread "ScriptThread PipelineId { namespace_id: PipelineNamespaceId(0), index: PipelineIndex(0) }"
  │ stack backtrace:
  │    0:     0x7fc58c206b8d - backtrace::backtrace::trace::h0e60ef08c7c34e9f
  │    1:     0x7fc58c207212 - backtrace::capture::Backtrace::new::h8bf319c36d8f5d1b
  │    2:     0x7fc58a9dfa94 - servo::install_crash_handler::handler::h40399914f600372a
  │    3:     0x7fc58834acaf - <unknown>
  │    4:     0x7fc58a9dfb1f - servo::install_crash_handler::handler::h40399914f600372a
  │    5:     0x7fc58bb1e1b3 - AsmJSFaultHandler
  │                         at /home/servo/.cargo/git/checkouts/mozjs-fa11ffc7d4f1cc2d/master/mozjs/js/src/asmjs/WasmSignalHandlers.cpp:1171
  │    6:     0x7fc5888ff32f - <unknown>
  └    7:     0x7fc576b9a000 - <unknown>

[jdm]

Tracking this non-test-specific problem in #19937.