Move StdStringExtractor to tools/debugserver

The class is only used in the debugserver. The rest of lldb has the StringExtractor class.

Xcode project will need to be updated after this.

llvm-svn: 281226
diff --git a/lldb/tools/debugserver/source/JSON.h b/lldb/tools/debugserver/source/JSON.h
index d395177..eee62f4 100644
--- a/lldb/tools/debugserver/source/JSON.h
+++ b/lldb/tools/debugserver/source/JSON.h
@@ -10,9 +10,7 @@
 #ifndef utility_JSON_h_
 #define utility_JSON_h_
 
-// This cross-project usage is fine as StdStringExtractor.h is entirely
-// self-contained.
-#include "lldb/Utility/StdStringExtractor.h"
+#include "StdStringExtractor.h"
 
 // C includes
 #include <inttypes.h>