Move core/include/fxcrt to core/fxcrt/include.

This CL moves the fxcrt code into the core/fxcrt directory. The only exception
was fx_bidi.h which was moved into core/fxcrt as it is not used outside of
core/.

R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1825953002 .
diff --git a/fpdfsdk/javascript/public_methods_embeddertest.cpp b/fpdfsdk/javascript/public_methods_embeddertest.cpp
index a298cfc..153b3cd 100644
--- a/fpdfsdk/javascript/public_methods_embeddertest.cpp
+++ b/fpdfsdk/javascript/public_methods_embeddertest.cpp
@@ -4,7 +4,7 @@
 
 #include <cmath>
 
-#include "core/include/fxcrt/fx_string.h"
+#include "core/fxcrt/include/fx_string.h"
 #include "fpdfsdk/javascript/PublicMethods.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/js_embedder_test.h"