Revert "Perform CPU sampling by CPU sampling thread only iff processing thread is not running."

src/flag-definitions.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 332 matching lines @@
 DEFINE_bool(always_full_compiler, false,
             "try to use the dedicated run-once backend for all code")
 DEFINE_int(max_opt_count, 10,
            "maximum number of optimization attempts before giving up.")
 
 // compilation-cache.cc
 DEFINE_bool(compilation_cache, true, "enable compilation cache")
 
 DEFINE_bool(cache_prototype_transitions, true, "cache prototype transitions")
 
-// cpu-profiler.cc
-DEFINE_int(cpu_profiler_sampling_period, 1000,
-           "CPU profiler sampling period in microseconds")
-
 // debug.cc
 DEFINE_bool(trace_debug_json, false, "trace debugging JSON request/response")
 DEFINE_bool(debugger_auto_break, true,
             "automatically set the debug break flag when debugger commands are "
             "in the queue")
 DEFINE_bool(enable_liveedit, true, "enable liveedit experimental feature")
 DEFINE_bool(break_on_abort, true, "always cause a debug break before aborting")
 
 // execution.cc
 // Slightly less than 1MB on 64-bit, since Windows' default stack size for
@@ skipping 356 matching lines @@
 #undef DEFINE_bool
 #undef DEFINE_int
 #undef DEFINE_string
 #undef DEFINE_implication
 
 #undef FLAG_MODE_DECLARE
 #undef FLAG_MODE_DEFINE
 #undef FLAG_MODE_DEFINE_DEFAULTS
 #undef FLAG_MODE_META
 #undef FLAG_MODE_DEFINE_IMPLICATIONS