Emscripten: Clean up flags for old node versions

These flags are only needed for node <= 16. Node 16 has been end of life since
October of 2023.

Author: hoodmane

configure

@@ -1619,34 +1619,6 @@ then
     [Emscripten/node*], [
       AC_PATH_TOOL([NODE], [node], [node])
       HOSTRUNNER="$NODE"
-      # bigint for ctypes c_longlong, c_longdouble
-      # no longer available in Node 16
-      AC_CACHE_CHECK([for node --experimental-wasm-bigint], [ac_cv_tool_node_wasm_bigint], [
-        if $NODE -v --experimental-wasm-bigint > /dev/null 2>&1; then
-          ac_cv_tool_node_wasm_bigint=yes
-        else
-          ac_cv_tool_node_wasm_bigint=no
-        fi
-      ])
-      AS_VAR_IF([ac_cv_tool_node_wasm_bigint], [yes], [
-        AS_VAR_APPEND([HOSTRUNNER], [" --experimental-wasm-bigint"])
-      ])
-
-      AS_VAR_IF([enable_wasm_pthreads], [yes], [
-        AS_VAR_APPEND([HOSTRUNNER], [" --experimental-wasm-threads"])
-        # no longer available in Node 16
-        AC_CACHE_CHECK([for node --experimental-wasm-bulk-memory], [ac_cv_tool_node_wasm_bulk_memory], [
-          if $NODE -v --experimental-wasm-bulk-memory > /dev/null 2>&1; then
-            ac_cv_tool_node_wasm_bulk_memory=yes
-          else
-            ac_cv_tool_node_wasm_bulk_memory=no
-          fi
-        ])
-        AS_VAR_IF([ac_cv_tool_node_wasm_bulk_memory], [yes], [
-          AS_VAR_APPEND([HOSTRUNNER], [" --experimental-wasm-bulk-memory"])
-        ])
-      ])
-
       AS_VAR_IF([host_cpu], [wasm64], [AS_VAR_APPEND([HOSTRUNNER], [" --experimental-wasm-memory64"])])
     ],
     dnl TODO: support other WASI runtimes