message: Add support for PLATFORM_*SIMULATOR
  The toolchain in Xcode 10 uses a new LC_BUILD_VERSION entry to identify
  simulator binaries. Add support for reading those to debugserver.
  The exisitng test testing that code is currently failling when run
  with Xcode 10, no need for a new test.
diff: @@ -607,6 +607,11 @@ const char *MachProcess::GetDeploymentInfo(const struct load_command& lc,
  }
  }
  #if defined (LC_BUILD_VERSION)
  +#ifndef PLATFORM_IOSSIMULATOR
  +#define PLATFORM_IOSSIMULATOR 7
  +#define PLATFORM_TVOSSIMULATOR 8
  +#define PLATFORM_WATCHOSSIMULATOR 9
  +#endif
  if (cmd == LC_BUILD_VERSION) {
  struct build_version_command build_vers;
  if (ReadMemory(load_command_address, sizeof(struct build_version_command),
  @@ -621,10 +626,13 @@ const char *MachProcess::GetDeploymentInfo(const struct load_command& lc,
  case PLATFORM_MACOS:
  return "macosx";
  case PLATFORM_IOS:
  + case PLATFORM_IOSSIMULATOR:
  return "ios";
  case PLATFORM_TVOS:
  + case PLATFORM_TVOSSIMULATOR:
  return "tvos";
  case PLATFORM_WATCHOS:
  + case PLATFORM_WATCHOSSIMULATOR:
  return "watchos";
  case PLATFORM_BRIDGEOS:
  return "bridgeos";
  