[test] Add task-delay-stress fuzzer configs

TBR=sergiyb@chromium.org
NOTRY=true

Bug: v8:8278
Change-Id: I000c31366f2b3d894208665ddb6cef49216099a6
Reviewed-on: https://chromium-review.googlesource.com/c/1273097Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56508}

tools/testrunner/num_fuzzer.py

@@ -55,6 +55,11 @@ class NumFuzzer(base_runner.BaseTestRunner):
     parser.add_option("--stress-gc", default=0, type="int",
                       help="probability [0-10] of adding --random-gc-interval "
                            "flag to the test")
+
+    # Stress tasks
+    parser.add_option("--stress-delay-tasks", default=0, type="int",
+                      help="probability [0-10] of adding --stress-delay-tasks "
+                           "flag to the test")
     parser.add_option("--stress-thread-pool-size", default=0, type="int",
                       help="probability [0-10] of adding --thread-pool-size "
                            "flag to the test")
@@ -129,6 +134,7 @@ class NumFuzzer(base_runner.BaseTestRunner):
                              options.stress_scavenge,
                              options.stress_compaction,
                              options.stress_gc,
+                             options.stress_delay_tasks,
                              options.stress_thread_pool_size])),
     })
     return variables
@@ -224,6 +230,7 @@ class NumFuzzer(base_runner.BaseTestRunner):
     add('scavenge', options.stress_scavenge)
     add('gc_interval', options.stress_gc)
     add('threads', options.stress_thread_pool_size)
+    add('delay', options.stress_delay_tasks)
     add('interrupt_budget', options.stress_interrupt_budget)
     add('deopt', options.stress_deopt, options.stress_deopt_min)
     return fuzzers

tools/testrunner/testproc/fuzzer.py

@@ -217,6 +217,12 @@ class CompactionFuzzer(Fuzzer):
       yield ['--stress-compaction-random']
 
 
+class TaskDelayFuzzer(Fuzzer):
+  def create_flags_generator(self, rng, test, analysis_value):
+    while True:
+      yield ['--stress-delay-tasks']
+
+
 class ThreadPoolSizeFuzzer(Fuzzer):
   def create_flags_generator(self, rng, test, analysis_value):
     while True:
@@ -269,6 +275,7 @@ class DeoptFuzzer(Fuzzer):
 
 FUZZERS = {
   'compaction': (None, CompactionFuzzer),
+  'delay': (None, TaskDelayFuzzer),
   'deopt': (DeoptAnalyzer, DeoptFuzzer),
   'gc_interval': (GcIntervalAnalyzer, GcIntervalFuzzer),
   'interrupt_budget': (None, InterruptBudgetFuzzer),