[test] Add thread-pool-size numfuzzer

NOTRY=true

Bug: v8:7455
Change-Id: Icb82e8196bc16b4c8b0eebb3c5820e6b3d581735
Reviewed-on: https://chromium-review.googlesource.com/924309Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51336}

tools/testrunner/num_fuzzer.py

@@ -55,6 +55,9 @@ 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")
+    parser.add_option("--stress-thread-pool-size", default=0, type="int",
+                      help="probability [0-10] of adding --thread-pool-size "
+                           "flag to the test")
 
     # Stress deopt
     parser.add_option("--stress-deopt", default=0, type="int",
@@ -117,7 +120,8 @@ class NumFuzzer(base_runner.BaseTestRunner):
       'gc_fuzzer': bool(max([options.stress_marking,
                              options.stress_scavenge,
                              options.stress_compaction,
-                             options.stress_gc])),
+                             options.stress_gc,
+                             options.stress_thread_pool_size])),
     })
     return variables
 
@@ -208,6 +212,7 @@ class NumFuzzer(base_runner.BaseTestRunner):
     add('marking', options.stress_marking)
     add('scavenge', options.stress_scavenge)
     add('gc_interval', options.stress_gc)
+    add('threads', options.stress_thread_pool_size)
     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 ThreadPoolSizeFuzzer(Fuzzer):
+  def create_flags_generator(self, rng, test, analysis_value):
+    while True:
+      yield ['--thread-pool-size=%d' % rng.randint(1, 8)]
+
+
 class InterruptBudgetFuzzer(Fuzzer):
   def create_flags_generator(self, rng, test, analysis_value):
     while True:
@@ -268,6 +274,7 @@ FUZZERS = {
   'interrupt_budget': (None, InterruptBudgetFuzzer),
   'marking': (MarkingAnalyzer, MarkingFuzzer),
   'scavenge': (ScavengeAnalyzer, ScavengeFuzzer),
+  'threads': (None, ThreadPoolSizeFuzzer),
 }