//xls/jit:function_jit_test flaky due to fuzz test timeouts

[mikex-oss]

Describe the bug
The fuzz tests TestPackedArrayWithType and TestPackedTupleWithType are flaky when run in all configurations, in OSS and internally.

To Reproduce

bazel test -c opt //xls/jit:function_jit_test --runs_per_test=1000 --test_filter=FunctionJitTest.TestPackedArrayWithType --test_sharding_strategy=disabled --test_timeout=60

TIMEOUT in 63 out of 1000 in 75.3s

bazel test -c opt //xls/jit:function_jit_test --runs_per_test=1000 --test_filter=FunctionJitTest.TestPackedTupleWithType --test_sharding_strategy=disabled --test_timeout=60

TIMEOUT in 10 out of 1000 in 75.1s

Expected behavior
The tests are not flaky.

Additional context

Some diagnostics for flaky tests run internally with an extended timeout of 5 minutes produces the following results:

TestPackedArrayWithType (timeout 300s):

Worker  0 (-c opt):                      test passed in 942 out of 1000 runs.
Worker  1 (-c opt --config asan):        test passed in 932 out of 1000 runs.
Worker  2 (-c opt --config msan):        test passed in 898 out of 1000 runs.
Worker  3 (-c opt --config tsan):        test passed in 938 out of 1000 runs.
Worker  4 (-c opt --config ubsan):       test passed in 955 out of 1000 runs.

TestPackedTupleWithType (timeout 300s):

Worker  0 (-c opt):                      test passed in 997 out of 1000 runs.
Worker  1 (-c opt --config asan):        test passed in 995 out of 1000 runs.
Worker  2 (-c opt --config msan):        test passed in 949 out of 1000 runs.
Worker  3 (-c opt --config tsan):        test passed in 995 out of 1000 runs.
Worker  4 (-c opt --config ubsan):       test passed in 992 out of 1000 runs.