Avoid warnings in tests when compiling without default features

[alamb]

When testing with

cargo test -p datafusion --no-default-features   -- pruning

I get this warning:

warning: unused import: `ListArray`
    --> datafusion/src/physical_plan/functions.rs:1278:25
     |
1278 |             Int32Array, ListArray, StringArray, UInt32Array, UInt64Array,
     |                         ^^^^^^^^^
     |
     = note: `#[warn(unused_imports)]` on by default

Because the test that uses it is not being compiled without the default features.

Thus move the use to the tests that need them.

[codecov-commenter]

Codecov Report

Merging #489 (ef38b41) into master (33ff660) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #489   +/-   ##
=======================================
  Coverage   75.80%   75.80%           
=======================================
  Files         153      153           
  Lines       25924    25924           
=======================================
  Hits        19652    19652           
  Misses       6272     6272           

Impacted Files	Coverage Δ
datafusion/src/physical_plan/functions.rs	92.70% <ø> (ø)

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