[alamb]

Which issue does this PR close?

N/A

Rationale for this change

While working on #6682 I noticed that the names of some or our integration tests are very confusing.
Specifically

cargo test --test

error: "--test" takes one argument.
Available tests:
    aggregate_fuzz
    config_from_env
    custom_sources
    dataframe
    dataframe_functions
    fifo
    integration-test               <-- these tests differ by 1 character! (this is in the sql crate)
    integration_test               <-- '_'  (this is in the optimizer crate)
    join_fuzz
    memory_limit
    merge_fuzz
    order_spill_fuzz
    parquet_exec
    path_partition
    provider_filter_pushdown
    repartition
    roundtrip_logical_plan
    roundtrip_physical_plan
    row
    serialize
    simplification
    sql_integration               <-- this is in the core crate, not the sql crate
    sqllogictests
    statistics
    tpcds_planning
    user_defined_aggregates
    user_defined_plan
    window_fuzz

What changes are included in this PR?

Rename the tests so:

Available tests:
    aggregate_fuzz
    config_from_env
    core_integration        <-- in the core crate
    custom_sources
    dataframe
    dataframe_functions
    fifo
    join_fuzz
    memory_limit
    merge_fuzz
    optimizer_integration        <-- in the optimizer crate
    order_spill_fuzz
    parquet_exec
    path_partition
    provider_filter_pushdown
    repartition
    roundtrip_logical_plan
    roundtrip_physical_plan
    row
    serialize
    simplification
    sql_integration        <-- in the sql crate
    sqllogictests
    statistics
    tpcds_planning
    user_defined_aggregates
    user_defined_plan
    window_fuzz

Are these changes tested?

CI runs these tests

Are there any user-facing changes?

no this is a developer experience only