Fix regex octal parsing to limit to 3 characters

[davidwendt]

Closes #10223

Fix the regex octal pattern logic to stop parsing after 3 digit characters.
Updated the gtest to include adjacent octal and digit characters.

[codecov]

Codecov Report

Merging #10233 (13e7093) into branch-22.04 (a7d88cd) will increase coverage by 0.04%.
The diff coverage is 0.00%.

@@               Coverage Diff                @@
##           branch-22.04   #10233      +/-   ##
================================================
+ Coverage         10.42%   10.47%   +0.04%     
================================================
  Files               119      122       +3     
  Lines             20603    20502     -101     
================================================
- Hits               2148     2147       -1     
+ Misses            18455    18355     -100     

Impacted Files	Coverage Δ
python/cudf/cudf/_fuzz_testing/fuzzer.py	0.00% <0.00%> (ø)
python/cudf/cudf/_fuzz_testing/io.py	0.00% <0.00%> (ø)
python/cudf/cudf/_fuzz_testing/main.py	0.00% <0.00%> (ø)
python/cudf/cudf/_version.py	0.00% <0.00%> (ø)
python/cudf/cudf/comm/gpuarrow.py	0.00% <0.00%> (ø)
python/cudf/cudf/core/_base_index.py	0.00% <0.00%> (ø)
python/cudf/cudf/core/column/categorical.py	0.00% <0.00%> (ø)
python/cudf/cudf/core/column/column.py	0.00% <0.00%> (ø)
python/cudf/cudf/core/column/datetime.py	0.00% <ø> (ø)
python/cudf/cudf/core/column/numerical.py	0.00% <0.00%> (ø)
... and 45 more

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[davidwendt]

@gpucibot merge