ARROW-6049: [C++] Support view from one dictionary type to another in Array::View

[wesm]

This tests for both dictionary as root type and dictionary in children

[codecov-io]

Codecov Report

Merging #5129 into master will increase coverage by 1.6%.
The diff coverage is 96%.

@@            Coverage Diff             @@
##           master    #5129      +/-   ##
==========================================
+ Coverage   87.62%   89.23%    +1.6%     
==========================================
  Files        1014      731     -283     
  Lines      145892   105078   -40814     
  Branches     1437        0    -1437     
==========================================
- Hits       127843    93765   -34078     
+ Misses      17687    11313    -6374     
+ Partials      362        0     -362

Impacted Files	Coverage Δ
cpp/src/arrow/array_view_test.cc	98.16% <100%> (+0.09%)	⬆️
cpp/src/arrow/array.cc	82.28% <88.88%> (-0.1%)	⬇️
cpp/src/plasma/thirdparty/ae/ae.c	70.75% <0%> (-0.95%)	⬇️
python/pyarrow/parquet.py	92.17% <0%> (-0.13%)	⬇️
python/pyarrow/tests/test_parquet.py	96.47% <0%> (-0.04%)	⬇️
js/src/util/fn.ts
go/arrow/memory/memory_avx2_amd64.go
rust/datafusion/src/execution/filter.rs
rust/arrow/src/csv/writer.rs
rust/datafusion/src/bin/main.rs
... and 279 more

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[wesm]

rebased

[wesm]

+1

[wesm]

Travis build https://travis-ci.org/wesm/arrow/builds/574452409