Merge bitcoin/bitcoin#28044: test: indexes, fix on error infinite loop

89ba8905f5 test: indexes, fix on error infinite loop (furszy)

Pull request description:

  Coming from https://github.com/bitcoin/bitcoin/pull/28036#issuecomment-1623813703, I thought that we were going to fix it there but seems that got merged without it for some reason.

  As index sync failures trigger a shutdown request without notifying `BaseIndex::BlockUntilSyncedToCurrentChain` in any way, we also need to check whether a shutdown was requested or not inside 'IndexWaitSynced'.

  Otherwise, any error inside the index sync process will hang the test forever.

ACKs for top commit:
  MarcoFalke:
    lgtm ACK 89ba8905f5
  jamesob:
    ACK 89ba890
  ryanofsky:
    Code review ACK 89ba8905f5. Just comment update since last review

Tree-SHA512: 1f6daf34e51d3fbc802799bfa4ac0ef0d8f774db5f9e2f5d35df18a77679778475c94efc3da1fb723ebaf3583e4075e4a5cbe4a5104ad0c50e2b32076e247b29

src/test/util/index.cpp

@@ -5,11 +5,18 @@
 #include <test/util/index.h>
 
 #include <index/base.h>
+#include <shutdown.h>
+#include <util/check.h>
 #include <util/time.h>
 
 void IndexWaitSynced(const BaseIndex& index)
 {
     while (!index.BlockUntilSyncedToCurrentChain()) {
+        // Assert shutdown was not requested to abort the test, instead of looping forever, in case
+        // there was an unexpected error in the index that caused it to stop syncing and request a shutdown.
+        Assert(!ShutdownRequested());
+
         UninterruptibleSleep(100ms);
     }
+    assert(index.GetSummary().synced);
 }