Turn --concurrent_typed_lowering on by default.

With the flag enabled, that phase runs in the background as part
of OptimizeGraph.

Bug: v8:7790
Change-Id: I313578c113be1fb76dfc315522906178bee1027d
Reviewed-on: https://chromium-review.googlesource.com/c/1268156Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56624}

src/compiler/js-heap-broker.h

@@ -242,7 +242,6 @@ class ContextRef : public HeapObjectRef {
   V(JSFunction, array_function)                    \
   V(JSFunction, object_function)                   \
   V(JSFunction, promise_function)                  \
-  V(Map, async_function_object_map)                \
   V(Map, fast_aliased_arguments_map)               \
   V(Map, initial_array_iterator_map)               \
   V(Map, initial_string_iterator_map)              \
@@ -261,6 +260,7 @@ class ContextRef : public HeapObjectRef {
 // Those are set by Bootstrapper::ExportFromRuntime, which may not yet have
 // happened when Turbofan is invoked via --always-opt.
 #define BROKER_OPTIONAL_NATIVE_CONTEXT_FIELDS(V) \
+  V(Map, async_function_object_map)              \
   V(Map, map_key_iterator_map)                   \
   V(Map, map_key_value_iterator_map)             \
   V(Map, map_value_iterator_map)                 \

src/flag-definitions.h

@@ -403,7 +403,7 @@ DEFINE_INT(concurrent_recompilation_delay, 0,
 DEFINE_BOOL(block_concurrent_recompilation, false,
             "block queued jobs until released")
 DEFINE_BOOL(
-    concurrent_typed_lowering, false,
+    concurrent_typed_lowering, true,
     "run optimizing compiler's typed lowering phase on a separate thread")
 DEFINE_IMPLICATION(future, concurrent_typed_lowering)
 DEFINE_BOOL(concurrent_inlining, false,