Properly track bootstrappedRealms in InMemoryPolarisMetaStoreManagerFactory (#1352)

Fixes #1351

Author: dimas-b

service/common/src/main/java/org/apache/polaris/service/persistence/InMemoryPolarisMetaStoreManagerFactory.java

@@ -97,13 +97,13 @@ public synchronized Supplier<TransactionalPersistence> getOrCreateSessionSupplie
   private void bootstrapRealmsAndPrintCredentials(List<String> realms) {
     RootCredentialsSet rootCredentialsSet = RootCredentialsSet.fromEnvironment();
     this.bootstrapRealms(realms, rootCredentialsSet);
-    bootstrappedRealms.addAll(realms);
   }
 
   @Override
   public Map<String, PrincipalSecretsResult> bootstrapRealms(
       Iterable<String> realms, RootCredentialsSet rootCredentialsSet) {
     Map<String, PrincipalSecretsResult> results = super.bootstrapRealms(realms, rootCredentialsSet);
+    bootstrappedRealms.addAll(results.keySet());
 
     Map<String, RootCredentials> presetCredentials = rootCredentialsSet.credentials();
     for (String realmId : realms) {
@@ -113,6 +113,9 @@ public Map<String, PrincipalSecretsResult> bootstrapRealms(
       }
 
       PrincipalSecretsResult principalSecrets = results.get(realmId);
+      if (principalSecrets == null) {
+        continue; // already bootstrapped (possible benign race)
+      }
 
       String msg =
           String.format(