"tighten" value and error for this test

On PHP >= 8.4 (with frameless functions), typical CPU utilization of
that `str_replace()` function is at around 51%, without frameless
functions (PHP <= 8.3) the CPU utilisation for `str_replace()` is at
about 99%, this runs that test always and makes sure we match both
cases.

Author: realFlowControl

.github/workflows/prof_correctness.yml

@@ -111,7 +111,6 @@ jobs:
           unset DD_PROFILING_ALLOCATION_SAMPLING_DISTANCE
 
       - name: Run allocation_time_combined test (PHP 8.4+)
-        if: fromJSON(matrix.php-version) >= 8.4
         run: |
           export DD_PROFILING_LOG_LEVEL=trace
           export DD_PROFILING_EXPERIMENTAL_FEATURES_ENABLED=1
@@ -182,7 +181,6 @@ jobs:
           pprof_path: profiling/tests/correctness/timeline/
 
       - name: Check profiler correctness for allocation_time_combined
-        if: fromJSON(matrix.php-version) >= 8.4
         uses: Datadog/prof-correctness/analyze@main
         with:
           expected_json: profiling/tests/correctness/allocation_time_combined.json

profiling/tests/correctness/allocation_time_combined.json

@@ -37,8 +37,8 @@
       "stack-content": [
         {
           "regular_expression": "<?php;main;standard\\|str_replace$",
-          "percent": 51,
-          "error_margin": 50
+          "percent": 70,
+          "error_margin": 30
         }
       ]
     }