Revert "Convert code to use boost::beast"

This reverts commit cc9c976b76.

src/test/jtx/WSClient_test.cpp

@@ -21,6 +21,7 @@
 #include <test/jtx/WSClient.h>
 #include <test/jtx.h>
 #include <ripple/beast/unit_test.h>
+#include <beast/core/handler_alloc.hpp>
 
 namespace ripple {
 namespace test {