[Core][Bugfix][Perf] Introduce MQLLMEngine to avoid asyncio OH (#8157)

Co-authored-by: Nick Hill <nickhill@us.ibm.com>
Co-authored-by: rshaw@neuralmagic.com <rshaw@neuralmagic.com>
Co-authored-by: Robert Shaw <114415538+robertgshaw2-neuralmagic@users.noreply.github.com>
Co-authored-by: Simon Mo <simon.mo@hey.com>

tests/utils.py

@@ -119,7 +119,7 @@ class RemoteOpenAIServer:
     def __exit__(self, exc_type, exc_value, traceback):
         self.proc.terminate()
         try:
-            self.proc.wait(3)
+            self.proc.wait(8)
         except subprocess.TimeoutExpired:
             # force kill if needed
             self.proc.kill()