Intermittent crash of /dom/nodes/ParentNode-querySelector-All.html

[KiChjang]

  ▶ CRASH [expected OK] /dom/nodes/ParentNode-querySelector-All.html
  │ 
  │ VMware, Inc.
  │ Gallium 0.4 on softpipe
  │ 3.3 (Core Profile) Mesa 17.2.0-devel
  │ Stack trace for thread "ScriptThread PipelineId { namespace_id: PipelineNamespaceId(0), index: PipelineIndex(NonZero(1)) }"
  │ stack backtrace:
  │    0:     0x7fd09584d4bc - backtrace::backtrace::trace::h68e6d1a5f4087a98
  │    1:     0x7fd09584d4f2 - backtrace::capture::Backtrace::new::h280d67af9041ceff
  │    2:     0x7fd09430e3fd - servo::install_crash_handler::handler::h64a2386b89cb8f28
  │    3:     0x7fd0964db5e3 - AsmJSFaultHandler
  │                         at /home/servo/.cargo/git/checkouts/mozjs-fa11ffc7d4f1cc2d/834ce35/mozjs/js/src/asmjs/WasmSignalHandlers.cpp:1171
  │    4:     0x7fd091fcc32f - <unknown>
  │    5:     0x7fd08f831222 - <unknown>
  │ Stack trace for thread "ScriptThread PipelineId { namespace_id: PipelineNamespaceId(0), index: PipelineIndex(NonZero(1)) }"
  │ stack backtrace:
  │    0:     0x7fd09584d4bc - backtrace::backtrace::trace::h68e6d1a5f4087a98
  │    1:     0x7fd09584d4f2 - backtrace::capture::Backtrace::new::h280d67af9041ceff
  │    2:     0x7fd09430e3fd - servo::install_crash_handler::handler::h64a2386b89cb8f28
  │    3:     0x7fd091a13caf - <unknown>
  │    4:     0x7fd09430e470 - servo::install_crash_handler::handler::h64a2386b89cb8f28
  │    5:     0x7fd0964db5e3 - AsmJSFaultHandler
  │                         at /home/servo/.cargo/git/checkouts/mozjs-fa11ffc7d4f1cc2d/834ce35/mozjs/js/src/asmjs/WasmSignalHandlers.cpp:1171
  │    6:     0x7fd091fcc32f - <unknown>
  └    7:     0x7fd08f831222 - <unknown>

[jdm]

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