Make jmh params configurable via command line args

[jack-berg]

The benchmarks we run in benchmark.yml use shared bare metal runners, so we want to be judicious with how much time our runs take.

Local runs don't have the same constraints, and it can be quite useful to run with more forks, more time, or more iterations to reduce variance.

This makes such customization easy by adding parameters.

For example:

# run with defaults defined in benchmark class
./gradlew :sdk:all:jmh -PjmhIncludeSingleClass=SpanRecordBenchmark

# override forks from 1 to 3 to reduce variance
./gradlew :sdk:all:jmh -PjmhIncludeSingleClass=SpanRecordBenchmark -PjmhFork=3

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.26%. Comparing base (984fd4f) to head (49f90a2).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #8305   +/-   ##
=========================================
  Coverage     90.25%   90.26%           
- Complexity     7687     7688    +1     
=========================================
  Files           850      850           
  Lines         23198    23198           
  Branches       2354     2354           
=========================================
+ Hits          20938    20940    +2     
+ Misses         1532     1531    -1     
+ Partials        728      727    -1     

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