Intermittent crash of /html/dom/reflection-sections.html

[KiChjang]

  ▶ CRASH [expected OK] /html/dom/reflection-sections.html
  │ 
  │ VMware, Inc.
  │ Gallium 0.4 on softpipe
  │ 3.3 (Core Profile) Mesa 12.0.1
  │ Stack trace for thread "ScriptThread PipelineId { namespace_id: PipelineNamespaceId(0), index: PipelineIndex(1) }"
  │ stack backtrace:
  │    0:     0x7fd0af9b571d - backtrace::backtrace::trace::h16372ee7bf1517e5
  │    1:     0x7fd0af9b5db2 - backtrace::capture::Backtrace::new::hcc43c50c4b11c693
  │    2:     0x7fd0af521b34 - servo::install_crash_handler::handler::hbd30f9f913d3e893
  │    3:     0x7fd0b0793de3 - AsmJSFaultHandler
  │                         at /home/servo/.cargo/git/checkouts/mozjs-fa11ffc7d4f1cc2d/master/mozjs/js/src/asmjs/WasmSignalHandlers.cpp:1171
  │    4:     0x7fd0ad3f432f - <unknown>
  │    5:     0x7fd0b1a43ed6 - <unknown>
  │ Stack trace for thread "ScriptThread PipelineId { namespace_id: PipelineNamespaceId(0), index: PipelineIndex(1) }"
  │ stack backtrace:
  │    0:     0x7fd0af9b571d - backtrace::backtrace::trace::h16372ee7bf1517e5
  │    1:     0x7fd0af9b5db2 - backtrace::capture::Backtrace::new::hcc43c50c4b11c693
  │    2:     0x7fd0af521b34 - servo::install_crash_handler::handler::hbd30f9f913d3e893
  │    3:     0x7fd0ace3fcaf - <unknown>
  │    4:     0x7fd0af521bbf - servo::install_crash_handler::handler::hbd30f9f913d3e893
  │    5:     0x7fd0b0793de3 - AsmJSFaultHandler
  │                         at /home/servo/.cargo/git/checkouts/mozjs-fa11ffc7d4f1cc2d/master/mozjs/js/src/asmjs/WasmSignalHandlers.cpp:1171
  │    6:     0x7fd0ad3f432f - <unknown>
  └    7:     0x7fd0b1a43ed6 - <unknown>

[jdm]

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