fix(profiling): remove _self_acquired_at after use (#11898)

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Author: taegyunkim

ddtrace/profiling/collector/_lock.py

@@ -185,6 +185,7 @@ def _release(self, inner_func, *args, **kwargs):
             # _self_acquired_at is only set when the acquire was captured
             # if it's not set, we're not capturing the release
             start = self._self_acquired_at
+            del self._self_acquired_at
 
         try:
             return inner_func(*args, **kwargs)

releasenotes/notes/profiling-lock-acquired-at-remove-c8b5b96130a46ca8.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    profiling: resolves an issue where lock release would have been captured
+    with a wrong acquire timestamp