[R] Add tests for filter() and arrange() with aggregation expressions

[HyukjinKwon]

Describe the enhancement requested

03f8ae7 added a couple of TODOs for testing aggregation expressions

arrow/r/R/dplyr-filter.R

Line 49 in 03f8ae7

# TODO: add a test for this

arrow/r/R/dplyr-arrange.R

Line 54 in 03f8ae7

# TODO: add a test for this

Component(s)

R