Conditionalize cpdfsdk_formfillenvironment.h inclusion in ijs_runtime.cpp

Shields the non-V8 build from some circular inclusions. Follow-on from
https://pdfium-review.googlesource.com/c/pdfium/+/84154.

Change-Id: Ice25819f50eed0840c03c2d23899fe4c83320034
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/84254
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Auto-Submit: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
diff --git a/fxjs/ijs_runtime.cpp b/fxjs/ijs_runtime.cpp
index 58a481d..0e09d54 100644
--- a/fxjs/ijs_runtime.cpp
+++ b/fxjs/ijs_runtime.cpp
@@ -4,10 +4,10 @@
 
 #include "fxjs/ijs_runtime.h"
 
-#include "fpdfsdk/cpdfsdk_formfillenvironment.h"
 #include "fxjs/cjs_runtimestub.h"
 
 #ifdef PDF_ENABLE_V8
+#include "fpdfsdk/cpdfsdk_formfillenvironment.h"
 #include "fxjs/cfxjs_engine.h"
 #include "fxjs/cjs_runtime.h"
 #ifdef PDF_ENABLE_XFA