[Backtracing][Linux] Also remove the status argument from Runtime module.

There's a separate declaration here because we can't include the `Backtrace.h`
header from inside `modules/Runtime/Runtime.h`.

rdar://110261712

Author: al45tair

stdlib/public/Backtracing/modules/Runtime/Runtime.h

@@ -32,7 +32,6 @@ bool _swift_backtrace_isThunkFunction(const char *rawName);
 char *_swift_backtrace_demangle(const char *rawName,
                                 size_t rawNameLength,
                                 char *outputBuffer,
-                                size_t *outputBufferSize,
-                                int *status);
+                                size_t *outputBufferSize);
 
 #endif // SWIFT_BACKTRACING_RUNTIME_H