Fix nesting of #ifdef

[aprantl]

Summary

This fixes a compile error when building for an arm64 host.

[aprantl]

Also move comment.

[davide]

LGTM

lldb/tools/debugserver/source/MacOSX/MachProcess.mm

if (lc.cmd == LC_UUID) {
       if (ReadMemory(load_cmds_p, sizeof(struct uuid_command), &uuidcmd) ==
           sizeof(struct uuid_command))
         uuid_copy(inf.uuid, uuidcmd.uuid);
     }
     if (DeploymentInfo deployment_info = GetDeploymentInfo(lc, load_cmds_p)) {
       // Simulator support. If the platform is ambiguous, use the dyld info.
       if (deployment_info.maybe_simulator) {
         // If dyld doesn't return a platform, use a heuristic.
-#if (defined(__x86_64__) || defined(__i386__))
         // If we are running on Intel macOS, it is safe to assume
         // this is really a back-deploying simulator binary.
         if (deployment_info.maybe_simulator) {
+#if (defined(__x86_64__) || defined(__i386__))
           switch (deployment_info.platform) {
           case PLATFORM_IOS:
             deployment_info.platform = PLATFORM_IOSSIMULATOR;
             break;
           case PLATFORM_TVOS:
             deployment_info.platform = PLATFORM_TVOSSIMULATOR;
             break;
           case PLATFORM_WATCHOS:
             deployment_info.platform = PLATFORM_WATCHOSSIMULATOR;
             break;
           }
 #else
           // On an Apple Silicon macOS host, there is no
           // ambiguity. The only binaries that use legacy load
           // commands are back-deploying native iOS binaries. All
           // simulator binaries use the newer, unambiguous
           // LC_BUILD_VERSION load commands.
           deployment_info.maybe_simulator = false;
 #endif
         }
       }
       const char *lc_platform = GetPlatformString(deployment_info.platform);
       // macCatalyst support.
       //
       // This handles two special cases:
       //