Use IPC row count info in IPC reader

[viirya]

Which issue does this PR close?

Closes #1783.

Rationale for this change

What changes are included in this PR?

Are there any user-facing changes?

[codecov-commenter]

Codecov Report

Merging #1796 (6b6f148) into master (73d552a) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1796   +/-   ##
=======================================
  Coverage   83.39%   83.39%           
=======================================
  Files         198      198           
  Lines       56205    56213    +8     
=======================================
+ Hits        46872    46881    +9     
+ Misses       9333     9332    -1     

Impacted Files	Coverage Δ
arrow/src/ipc/reader.rs	90.82% <100.00%> (+0.08%)	⬆️
parquet_derive/src/parquet_field.rs	65.75% <0.00%> (-0.23%)	⬇️
parquet/src/encodings/encoding.rs	93.46% <0.00%> (-0.20%)	⬇️
arrow/src/ipc/gen/Message.rs	35.39% <0.00%> (+0.74%)	⬆️

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