Test format stuck with 2mb cache

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#  RUN PARAMETERS

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abort=0

auto_throttle=1

backups=0

bitcnt=1

bloom=1

bloom_bit_count=9

bloom_hash_count=4

bloom_oldest=0

cache=2

checkpoints=1

checksum=uncompressed

chunk_size=8

compaction=0

compression=snappy

data_extend=0

data_source=file

delete_pct=31

dictionary=0

direct_io=0

encryption=rotn-7

evict_max=0

file_type=row-store

firstfit=0

huffman_key=0

huffman_value=0

in_memory=0

insert_pct=42

internal_key_truncation=1

internal_page_max=9

isolation=read-uncommitted

key_gap=2

key_max=256

key_min=256

leaf_page_max=9

leak_memory=0

logging=1

logging_archive=0

logging_compression=snappy

logging_prealloc=0

long_running_txn=0

lsm_worker_threads=3

merge_max=20

mmap=1

ops=100000

prefix_compression=1

prefix_compression_min=5

quiet=1

repeat_data_pct=33

reverse=0

rows=100000

runs=1

rebalance=1

salvage=1

split_pct=70

statistics=0

statistics_server=0

threads=2

timer=20

transaction-frequency=21

value_max=2786

value_min=256

verify=1

wiredtiger_config=

write_pct=83

############################################

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cache dump

file:wt(checkpoint=WiredTigerCheckpoint.3):

        internal: 149 pages, 1MB, 149/0 clean/dirty pages, 1/0 clean/dirty MB, 0MB max page, 0MB max dirty page

        leaf: 1 pages, 0MB, 1/0 clean/dirty pages, 0/0 clean/dirty MB, 0MB max page, 0MB max dirty page

file:wt(<live>):

        internal: 81 pages, 0MB, 5/76 clean/dirty pages, 0/0 clean/dirty MB, 0MB max page, 0MB max dirty page

file:WiredTigerLAS.wt(<live>):

        internal: 1 pages, 0MB, 1/0 clean/dirty pages, 0/0 clean/dirty MB, 0MB max page, 0MB max dirty page

file:WiredTiger.wt(<live>):

        internal: 1 pages, 0MB, 1/0 clean/dirty pages, 0/0 clean/dirty MB, 0MB max page, 0MB max dirty page

cache dump: total found = 1MB vs tracked inuse 1MB

total dirty bytes = 0MB

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