[foozzie] Make correctness runs deterministic

NOTRY=true

Bug: chromium:829681
Change-Id: Iccf9b190e77b1c27fedec74d67f5948803dd1fa9
Reviewed-on: https://chromium-review.googlesource.com/998355Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52437}

tools/clusterfuzz/testdata/failure_output.txt

@@ -9,9 +9,9 @@
 # Compared x64,ignition with x64,ignition_turbo
 #
 # Flags of x64,ignition:
---abort_on_stack_or_string_length_overflow --expose-gc --allow-natives-syntax --invoke-weak-callbacks --omit-quit --es-staging --random-seed 12345 --turbo-filter=~ --noopt --suppress-asm-messages
+--abort_on_stack_or_string_length_overflow --expose-gc --allow-natives-syntax --invoke-weak-callbacks --omit-quit --es-staging --wasm-num-compilation-tasks=0 --random-seed 12345 --turbo-filter=~ --noopt --suppress-asm-messages
 # Flags of x64,ignition_turbo:
---abort_on_stack_or_string_length_overflow --expose-gc --allow-natives-syntax --invoke-weak-callbacks --omit-quit --es-staging --random-seed 12345 --suppress-asm-messages --stress-scavenge=100
+--abort_on_stack_or_string_length_overflow --expose-gc --allow-natives-syntax --invoke-weak-callbacks --omit-quit --es-staging --wasm-num-compilation-tasks=0 --random-seed 12345 --suppress-asm-messages --stress-scavenge=100
 #
 # Difference:
 - unknown

tools/clusterfuzz/v8_foozzie.py

@@ -106,7 +106,7 @@ ARCH_MOCKS = os.path.join(BASE_PATH, 'v8_mock_archs.js')
 
 FLAGS = ['--abort_on_stack_or_string_length_overflow', '--expose-gc',
          '--allow-natives-syntax', '--invoke-weak-callbacks', '--omit-quit',
-         '--es-staging']
+         '--es-staging', '--wasm-num-compilation-tasks=0']
 
 SUPPORTED_ARCHS = ['ia32', 'x64', 'arm', 'arm64']