binaryen.js: Remove closure flags that set the ES version (WebAssembly#6157)

Emscripten sets that itself these days.

Author: kripken

CMakeLists.txt

@@ -470,7 +470,6 @@ if(EMSCRIPTEN)
   target_link_libraries(binaryen_wasm "-msign-ext")
   target_link_libraries(binaryen_wasm "-mbulk-memory")
   target_link_libraries(binaryen_wasm optimized "--closure=1")
-  target_link_libraries(binaryen_wasm optimized "--closure-args=\"--language_in=ECMASCRIPT6 --language_out=ECMASCRIPT6\"")
   # TODO: Fix closure warnings! (#5062)
   target_link_libraries(binaryen_wasm optimized "-Wno-error=closure")
   target_link_libraries(binaryen_wasm optimized "-flto")
@@ -513,9 +512,7 @@ if(EMSCRIPTEN)
   target_link_libraries(binaryen_js optimized "--closure=1")
   # Currently, js_of_ocaml can only process ES5 code
   if(JS_OF_OCAML)
-    target_link_libraries(binaryen_js optimized "--closure-args=\"--language_in=ECMASCRIPT6 --language_out=ECMASCRIPT5\"")
-  else()
-    target_link_libraries(binaryen_js optimized "--closure-args=\"--language_in=ECMASCRIPT6 --language_out=ECMASCRIPT6\"")
+    target_link_libraries(binaryen_js optimized "--closure-args=\"--language_out=ECMASCRIPT5\"")
   endif()
   # TODO: Fix closure warnings! (#5062)
   target_link_libraries(binaryen_js optimized "-Wno-error=closure")