Fix ORC writer OOM issue

[vuule]

Closes #7588

The stream size used to be calculated incorrectly, leading to huge allocation for the encoded data buffer.

This PR fixes the stream size computation to count each row group only once.

[codecov]

Codecov Report

Merging #7605 (8b01212) into branch-0.19 (7871e7a) will increase coverage by 0.52%.
The diff coverage is 92.89%.

@@               Coverage Diff               @@
##           branch-0.19    #7605      +/-   ##
===============================================
+ Coverage        81.86%   82.39%   +0.52%     
===============================================
  Files              101      101              
  Lines            16884    17350     +466     
===============================================
+ Hits             13822    14295     +473     
+ Misses            3062     3055       -7     

Impacted Files	Coverage Δ
python/cudf/cudf/core/index.py	93.34% <ø> (+0.48%)	⬆️
python/cudf/cudf/core/column/column.py	87.86% <60.00%> (+0.10%)	⬆️
python/cudf/cudf/core/column/numerical.py	94.83% <85.71%> (-0.20%)	⬇️
python/cudf/cudf/core/frame.py	89.09% <89.18%> (+0.08%)	⬆️
python/cudf/cudf/core/column/decimal.py	92.75% <90.32%> (-2.12%)	⬇️
python/cudf/cudf/core/dataframe.py	90.58% <95.00%> (+0.11%)	⬆️
python/cudf/cudf/core/series.py	91.57% <96.22%> (+0.79%)	⬆️
python/cudf/cudf/core/column/string.py	86.76% <100.00%> (+0.26%)	⬆️
python/cudf/cudf/core/column_accessor.py	95.45% <100.00%> (+0.14%)	⬆️
python/cudf/cudf/core/dtypes.py	91.13% <100.00%> (+1.40%)	⬆️
... and 56 more

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[vuule]

rerun tests

[vuule]

rerun tests

[vuule]

@gpucibot merge