Revert of Revert of Turn on job based recompilation

src/flag-definitions.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file defines all of the flags.  It is separated into different section,
 // for Debug, Release, Logging and Profiling, etc.  To add a new flag, find the
 // correct section, and use one of the DEFINE_ macros, without a trailing ';'.
 //
 // This include does not have a guard, because it is a template-style include,
 // which can be included multiple times in different modes.  It expects to have
@@ skipping 349 matching lines @@
 DEFINE_BOOL(inline_construct, true, "inline constructor calls")
 DEFINE_BOOL(inline_arguments, true, "inline functions with arguments object")
 DEFINE_BOOL(inline_accessors, true, "inline JavaScript accessors")
 DEFINE_INT(escape_analysis_iterations, 2,
            "maximum number of escape analysis fix-point iterations")
 
 DEFINE_BOOL(optimize_for_in, true, "optimize functions containing for-in loops")
 
 DEFINE_BOOL(concurrent_recompilation, true,
             "optimizing hot functions asynchronously on a separate thread")
-DEFINE_BOOL(job_based_recompilation, false,
+DEFINE_BOOL(job_based_recompilation, true,
             "post tasks to v8::Platform instead of using a thread for "
             "concurrent recompilation")
 DEFINE_BOOL(trace_concurrent_recompilation, false,
             "track concurrent recompilation")
 DEFINE_INT(concurrent_recompilation_queue_length, 8,
            "the length of the concurrent compilation queue")
 DEFINE_INT(concurrent_recompilation_delay, 0,
            "artificial compilation delay in ms")
 DEFINE_BOOL(block_concurrent_recompilation, false,
             "block queued jobs until released")
@@ skipping 638 matching lines @@
 #undef DEFINE_ALIAS_FLOAT
 #undef DEFINE_ALIAS_ARGS
 
 #undef FLAG_MODE_DECLARE
 #undef FLAG_MODE_DEFINE
 #undef FLAG_MODE_DEFINE_DEFAULTS
 #undef FLAG_MODE_META
 #undef FLAG_MODE_DEFINE_IMPLICATIONS
 
 #undef COMMA