Remove and recreate expected values dir in white-box testing 2nd half

[hx235]

Context:
#8913 (comment)

Test:

• Locally run python3 ./tools/db_crashtest.py whitebox --simple -max_key=1000000 -value_size_mult=33 -write_buffer_size=524288 -target_file_size_base=524288 -max_bytes_for_level_base=2097152 --duration=120 --interval=10 --ops_per_thread=1000 --random_kill_odd=887
• CI stress testing

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[ajkr]

LGTM. Was it really failing silently? I thought whitebox crash test H2 should catch unexpected crashes since kill_random_test is often None

[hx235]

LGTM. Was it really failing silently? I thought whitebox crash test H2 should catch unexpected crashes since kill_random_test is often None

Maybe the first half often runs super long so second half doesn't get to run many iterations to hit sync_fault_injection=1 (only after it is re-enabled is stress test) or disable_wal=1??