chore(iast): improve microbenchmarks accuracy (#13160)

- remove `loops` and `value` config from appsec_iast_aspects/config.yaml
and use the default values
- split `appsec_iast_aspects` into smaller steps due to the default
values returns timeout in the CI
- Fix exception in `appsec_iast_propagation/scenario.py`
```
 File "/app/benchmarks/.venv_baseline/lib/python3.9/site-packages/pyperf/_runner.py", line 494, in task_func
    return time_func(loops, *args)
  File "/app/benchmarks/bm/_scenario.py", line 64, in _pyperf
    run(loops)
  File "/app/benchmarks/scenario.py", line 99, in _
    launch_function(self.iast_enabled, func, self.internal_loop, caller_loop)
  File "/app/benchmarks/scenario.py", line 81, in launch_function
    tainted_value = new_request(enable_propagation)
  File "/app/benchmarks/scenario.py", line 75, in new_request
    taint_pyobject_with_ranges(tainted, (CHECK_RANGES[0],))
  File "/app/benchmarks/scenario.py", line 41, in taint_pyobject_with_ranges
    set_ranges(pyobject, tuple(ranges))
ValueError: iast::propagation::native::error::Tainted Map isn't initialized
Traceback (most recent call last):
```
## Checklist
- [x] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
- Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

Author: avara1986

.gitlab/benchmarks/microbenchmarks.yml

@@ -144,6 +144,9 @@ microbenchmarks:
         - "core_api"
         - "otel_span"
         - "appsec_iast_aspects"
+        - "appsec_iast_aspects_ospath"
+        - "appsec_iast_aspects_re_module"
+        - "appsec_iast_aspects_split"
         - "appsec_iast_django_startup"
         - "appsec_iast_propagation"
         # Flaky. Timeout errors