Added a test

Author: vfdev-5

mlir/test/python/ir/context_lifecycle.py

@@ -47,3 +47,17 @@
 assert '"mlir.ir.Context._CAPIPtr"' in repr(c4_capsule)
 c5 = mlir.ir.Context._CAPICreate(c4_capsule)
 assert c4 is c5
+c4 = None
+c5 = None
+gc.collect()
+
+# Create a global threadpool and use it in two contexts
+tp = mlir.ir.ThreadPool()
+assert tp.get_max_concurrency() > 0
+c5 = mlir.ir.Context()
+c5.enable_multithreading(False)
+c5.set_thread_pool(tp)
+c6 = mlir.ir.Context()
+c6.enable_multithreading(False)
+c6.set_thread_pool(tp)
+assert mlir.ir.Context._get_live_count() == 2