[Backtracing] Also update the Linux crash handler, now it's merged.

The Linux crash handler should have the same `output-to` behaviour
as on macOS.

rdar://110371557

stdlib/public/runtime/CrashHandlerLinux.cpp

@@ -617,6 +617,8 @@ const char *backtracer_argv[] = {
  "preset", // 26
  "--cache", // 27
  "true", // 28
+ "--output-to", // 29
+ "stdout", // 30
  NULL
 };
 
@@ -769,6 +771,16 @@ run_backtracer(int memserver_fd)
  break;
  }
 
+ switch (_swift_backtraceSettings.outputTo) {
+ case OutputTo::Stdout:
+ backtracer_argv[30] = "stdout";
+ break;
+ case OutputTo::Auto: // Shouldn't happen, but if it does pick stderr
+ case OutputTo::Stderr:
+ backtracer_argv[30] = "stderr";
+ break;
+ }
+
  backtracer_argv[28] = trueOrFalse(_swift_backtraceSettings.cache);
 
  format_unsigned(_swift_backtraceSettings.timeout, timeout_buf);