[wasm] Enable native-heap WebAssembly code by default.

R=titzer@chromium.org
BUG=v8:6876

Change-Id: Ib9821123e89b4a198cfa921ffd4cf5bee55cc93d
Reviewed-on: https://chromium-review.googlesource.com/856999Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50498}

src/flag-definitions.h

@@ -493,7 +493,7 @@ DEFINE_INT(wasm_num_compilation_tasks, 10,
            "number of parallel compilation tasks for wasm")
 DEFINE_DEBUG_BOOL(wasm_trace_native_heap, false,
                   "trace wasm native heap events")
-DEFINE_BOOL(wasm_jit_to_native, false,
+DEFINE_BOOL(wasm_jit_to_native, true,
             "JIT wasm code to native (not JS GC) memory")
 DEFINE_IMPLICATION(future, wasm_jit_to_native)
 DEFINE_BOOL(wasm_trace_serialization, false,