Reland "Disable the CompilerDispatcher if we don't have idle time"

src/flag-definitions.h

Index: src/flag-definitions.h
diff --git a/src/flag-definitions.h b/src/flag-definitions.h
index 9195b55c4cba4937267d093504a1403601e50f06..971879a23f02089da0115f28f5f6d54e244f99ae 100644
--- a/src/flag-definitions.h
+++ b/src/flag-definitions.h
@@ -300,6 +300,7 @@ DEFINE_BOOL(string_slices, true, "use string slices")
 DEFINE_BOOL(ignition, false, "use ignition interpreter")
 DEFINE_BOOL(ignition_staging, false, "use ignition with all staged features")
 DEFINE_IMPLICATION(ignition_staging, ignition)
+DEFINE_IMPLICATION(ignition_staging, compiler_dispatcher)
 DEFINE_STRING(ignition_filter, "*", "filter for ignition interpreter")
 DEFINE_BOOL(ignition_deadcode, true,
             "use ignition dead code elimination optimizer")
@@ -666,6 +667,9 @@ DEFINE_BOOL(compilation_cache, true, "enable compilation cache")
 
 DEFINE_BOOL(cache_prototype_transitions, true, "cache prototype transitions")
 
+// compiler-dispatcher.cc
+DEFINE_BOOL(compiler_dispatcher, false, "enable compiler dispatcher")
+
 // cpu-profiler.cc
 DEFINE_INT(cpu_profiler_sampling_interval, 1000,
            "CPU profiler sampling interval in microseconds")