[BENCHMARK] add SpanData recordable benchmark and unify common utils

[dbarker]

Contributes to #4046

Changes

• Adds common span recordable benchmark utils to test common
  • common data and helpers to test recording spans with varying numbers of attributes, events, and links
• Adds a SpanData recordable benchmark.
• Update OtlpRecordable benchmark use the common uitls

For significant contributions please make sure you have completed the following items:

• CHANGELOG.md updated for non-trivial changes
• Unit tests have been added
• Changes in public API reviewed

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.78%. Comparing base (938eab8) to head (0f80782).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4203      +/-   ##
==========================================
- Coverage   82.79%   82.78%   -0.00%     
==========================================
  Files         415      415              
  Lines       17452    17450       -2     
==========================================
- Hits        14447    14445       -2     
  Misses       3005     3005              

Files with missing lines	Coverage Δ
sdk/src/trace/span_data.cc	98.42% <100.00%> (-0.04%)	⬇️

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[dbarker]

Comparing SpanData to OtlpRecordable performance on the recording benchmark cases from this PR (otlp_recordable_benchmark/span_data_benchmark) shows that recording span attributes, events, and links into the SpanData recordable (backed by STL types) outperforms recording into OtlpRecordable (backed by the protobuf span type).

This is interesting because SpanData enforces attribute key uniqueness (OltpRecordable does not) and it can meet requirements for additional span Readable/ReadWriteSpan interfaces.

---

Benchmark	OtlpRecordable mean (ns)	SpanData mean (ns)	% Difference	CV Otlp	CV SpanData
RecordMinimalSpan	362	341	−5.8%	0.49%	0.28%
RecordNominalSpan	638	581	−8.9%	1.26%	2.63%
RecordSpanWithAttributes/1	414	390	−5.8%	0.47%	1.07%
RecordSpanWithAttributes/10	880	705	−19.9%	1.46%	0.90%
RecordSpanWithAttributes/128	7293	7479	+2.6%	11.55%	2.53%
RecordSpanWithEvents/1	502	456	−9.2%	0.21%	0.63%
RecordSpanWithEvents/10	1705	1584	−7.1%	1.70%	1.54%
RecordSpanWithEvents/128	16750	16434	−1.9%	1.71%	1.28%
RecordSpanWithLinks/1	511	435	−14.9%	1.13%	0.49%
RecordSpanWithLinks/10	1784	1368	−23.3%	0.34%	1.63%
RecordSpanWithLinks/128	19515	15304	−21.6%	12.31%	6.08%

[marcalff]

LGTM, thanks for the benchmark utilities.

This will help a lot.

[marcalff]

The only changes in production code is 2 lines in span_data.cc, which should improve performances.
Everything else is test code for benchmarks.
Assessment is low risk, merging now.