Some code cleanups and improvements around the various DTC visitor implementations in SkyQuery:

(1) Get rid of the 'errorReporter' param used in the two unbounded 'deps' implementations. In practice, this callback is always used right alongside the normal query callback. So we can re-implement it as a single, composite callback.

(2) Revert the recent change to processResultsAndReturnTargets (and restore the old method name). It general, it's a bad idea to return Targets outside that method, because it means we aren't respecting the MultisetSemaphore<PackageIdentifier>. Along with (1), this fixes a real issue where DepsUnboundedVisitor#processPartialResults was using Targets (and thus keeping their Packages live in memory) outside of the package semaphore.

RELNOTES: None
PiperOrigin-RevId: 206606747
diff --git a/src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java b/src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java
index cba76ba..0c759a8 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java
@@ -1217,16 +1217,14 @@
   public QueryTaskFuture<Void> getDepsUnboundedParallel(
       QueryExpression expression,
       QueryExpressionContext<Target> context,
-      Callback<Target> callback,
-      Callback<Target> errorReporter) {
+      Callback<Target> callback) {
     return ParallelSkyQueryUtils.getDepsUnboundedParallel(
         SkyQueryEnvironment.this,
         expression,
         context,
         callback,
         packageSemaphore,
-        /*depsNeedFiltering=*/ !dependencyFilter.equals(DependencyFilter.ALL_DEPS),
-        errorReporter);
+        /*depsNeedFiltering=*/ !dependencyFilter.equals(DependencyFilter.ALL_DEPS));
   }
 
   @ThreadSafe