Remove the workaround for gcc bug.43949?

[Chandlerooo]

I notice there is a trivial workaround for gcc bug 43949:
https://github.com/servo/mozjs/blob/master/mozjs/js/src/jit/arm/Simulator-arm.cpp

int32_t Simulator::get_register(int reg) const {
  MOZ_ASSERT(reg >= 0 && reg < num_registers);
  // Work around GCC bug: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43949
  if (reg >= num_registers) return 0;
  return registers_[reg] + ((reg == pc) ? SimInstruction::kPCReadOffset : 0);
}

This compiler bug is already marked as fixed :
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43949
Shall this workaround be removed?

[jdm]

This code is imported from upstream releases that originate from Firefox. We only apply patches that fix problems that affect Servo directly.