Add adjust_os_scheduling_parameters flag for v8 isolate

This will allow the test infrastructure to bypass isolate scheduling
restrictions.


Bug: chromium:1002582
Change-Id: Ib22a599cf6c826c3d412898520dba6f4045175b2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1801995Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Fernando Serboncini <fserb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63811}

src/execution/isolate.cc

@@ -320,7 +320,9 @@ Isolate::FindOrAllocatePerThreadDataForThisThread() {
     base::MutexGuard lock_guard(&thread_data_table_mutex_);
     per_thread = thread_data_table_.Lookup(thread_id);
     if (per_thread == nullptr) {
-      base::OS::AdjustSchedulingParams();
+      if (FLAG_adjust_os_scheduling_parameters) {
+        base::OS::AdjustSchedulingParams();
+      }
       per_thread = new PerIsolateThreadData(this, thread_id);
       thread_data_table_.Insert(per_thread);
     }

src/flags/flag-definitions.h

@@ -1238,6 +1238,8 @@ DEFINE_BOOL(print_all_exceptions, false,
 DEFINE_BOOL(
     detailed_error_stack_trace, false,
     "includes arguments for each function call in the error stack frames array")
+DEFINE_BOOL(adjust_os_scheduling_parameters, true,
+            "adjust OS specific scheduling params for the isolate")
 
 // runtime.cc
 DEFINE_BOOL(runtime_call_stats, false, "report runtime call counts and times")