test: Avoid accessing free'd memory in validation_chainstatemanager_t…

…ests

Summary: Backport of core [[bitcoin/bitcoin#18615 | PR18615]].

Test Plan:
With TSAN:
  ninja check

Reviewers: #bitcoin_abc, majcosta

Reviewed By: #bitcoin_abc, majcosta

Differential Revision: https://reviews.bitcoinabc.org/D8639

src/test/txindex_tests.cpp

@@ -74,12 +74,9 @@ BOOST_FIXTURE_TEST_CASE(txindex_initial_sync, TestChain100Setup) {
     // shutdown sequence (c.f. Shutdown() in init.cpp)
     txindex.Stop();
 
-    // txindex job may be scheduled, so stop scheduler before destructing
-    m_node.scheduler->stop();
-    threadGroup.interrupt_all();
-    threadGroup.join_all();
-
-    // Rest of shutdown sequence and destructors happen in ~TestingSetup()
+    // Let scheduler events finish running to avoid accessing any memory related
+    // to txindex after it is destructed
+    SyncWithValidationInterfaceQueue();
 }
 
 BOOST_AUTO_TEST_SUITE_END()

src/test/validation_chainstatemanager_tests.cpp

@@ -9,6 +9,7 @@
 #include <sync.h>
 #include <test/util/setup_common.h>
 #include <validation.h>
+#include <validationinterface.h>
 
 #include <vector>
 
@@ -100,7 +101,10 @@ BOOST_AUTO_TEST_CASE(chainstatemanager) {
     exp_tip = c1.m_chain.Tip();
     BOOST_CHECK_EQUAL(validated_tip, exp_tip);
 
-    // Avoid triggering the address sanitizer.
+    // Let scheduler events finish running to avoid accessing memory that is
+    // going to be unloaded
+    SyncWithValidationInterfaceQueue();
+
     WITH_LOCK(::cs_main, manager.Unload());
 }