Revert "Stop using deprecated ImmutableMap.Builder#build() method"

Revert submission 328340-useImmutableMap#buildOrThrow

Reverting because of 329499: Revert "Upgrade guava to 31.0.1-jre" | https://gerrit-review.googlesource.com/c/gerrit/+/329499

Can be un-reverted after that change is un-reverted.

Reverted Changes:
Ia26b72188:Stop using deprecated ImmutableMap.Builder#build()...
I7a4fcfcf4:Stop using deprecated ImmutableMap.Builder#build()...

Change-Id: I1ed85aebfc4c5218a8a78a4d262e879b8a21c184
diff --git a/java/com/google/gerrit/plugins/codeowners/restapi/CheckCodeOwnerConfigFiles.java b/java/com/google/gerrit/plugins/codeowners/restapi/CheckCodeOwnerConfigFiles.java
index 18fa7ba..1b931ba 100644
--- a/java/com/google/gerrit/plugins/codeowners/restapi/CheckCodeOwnerConfigFiles.java
+++ b/java/com/google/gerrit/plugins/codeowners/restapi/CheckCodeOwnerConfigFiles.java
@@ -135,7 +135,7 @@
                 resultsByBranchBuilder.put(
                     branchNameKey.branch(),
                     checkBranch(input.path, branchNameKey, input.verbosity)));
-    return Response.ok(resultsByBranchBuilder.buildOrThrow());
+    return Response.ok(resultsByBranchBuilder.build());
   }
 
   private ImmutableSet<BranchNameKey> branches(ProjectResource projectResource)
diff --git a/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/GetOwnedPathsIT.java b/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/GetOwnedPathsIT.java
index b846598..5b19b9a 100644
--- a/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/GetOwnedPathsIT.java
+++ b/javatests/com/google/gerrit/plugins/codeowners/acceptance/api/GetOwnedPathsIT.java
@@ -728,7 +728,7 @@
       files.put(String.format("foo-%d.txt", i), "file content");
     }
 
-    String changeId = createChange("test change", files.buildOrThrow()).getChangeId();
+    String changeId = createChange("test change", files.build()).getChangeId();
 
     OwnedPathsInfo ownedPathsInfo =
         changeCodeOwnersApiFactory