Change Spawn.get{Tool,Input}Files to NestedSet

I think this should basically be a no-op. In a few places, it delays
flattening of the nested set, and could potentially reduce peak memory
use / reduce the time we're holding onto a flattened copy of the inputs.

PiperOrigin-RevId: 288673175
diff --git a/src/main/java/com/google/devtools/build/lib/exec/StandaloneTestStrategy.java b/src/main/java/com/google/devtools/build/lib/exec/StandaloneTestStrategy.java
index c266278..e0cf8d0 100644
--- a/src/main/java/com/google/devtools/build/lib/exec/StandaloneTestStrategy.java
+++ b/src/main/java/com/google/devtools/build/lib/exec/StandaloneTestStrategy.java
@@ -17,12 +17,12 @@
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Lists;
 import com.google.common.io.ByteStreams;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.devtools.build.lib.actions.ActionExecutionContext;
 import com.google.devtools.build.lib.actions.ActionInputHelper;
-import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.actions.ArtifactPathResolver;
 import com.google.devtools.build.lib.actions.EnvironmentalExecException;
 import com.google.devtools.build.lib.actions.ExecException;
@@ -43,6 +43,8 @@
 import com.google.devtools.build.lib.buildeventstream.BuildEventStreamProtos;
 import com.google.devtools.build.lib.buildeventstream.BuildEventStreamProtos.TestResult.ExecutionInfo;
 import com.google.devtools.build.lib.buildeventstream.TestFileNameConstants;
+import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
+import com.google.devtools.build.lib.collect.nestedset.Order;
 import com.google.devtools.build.lib.events.Reporter;
 import com.google.devtools.build.lib.util.OS;
 import com.google.devtools.build.lib.util.Pair;
@@ -132,9 +134,9 @@
             ImmutableMap.copyOf(executionInfo),
             action.getRunfilesSupplier(),
             ImmutableMap.of(),
-            /*inputs=*/ action.getInputs().toList(),
-            /*tools=*/ ImmutableList.<Artifact>of(),
-            ImmutableList.copyOf(action.getSpawnOutputs()),
+            /*inputs=*/ action.getInputs(),
+            /*tools=*/ NestedSetBuilder.emptySet(Order.STABLE_ORDER),
+            ImmutableSet.copyOf(action.getSpawnOutputs()),
             localResourceUsage);
     return new StandaloneTestRunnerSpawn(
         action, actionExecutionContext, spawn, tmpDir, workingDirectory, execRoot);
@@ -398,9 +400,10 @@
         ImmutableMap.copyOf(action.getExecutionInfo()),
         null,
         ImmutableMap.of(),
-        /*inputs=*/ ImmutableList.of(action.getTestXmlGeneratorScript(), action.getTestLog()),
-        /*tools=*/ ImmutableList.<Artifact>of(),
-        /*outputs=*/ ImmutableList.of(ActionInputHelper.fromPath(action.getXmlOutputPath())),
+        /*inputs=*/ NestedSetBuilder.create(
+            Order.STABLE_ORDER, action.getTestXmlGeneratorScript(), action.getTestLog()),
+        /*tools=*/ NestedSetBuilder.emptySet(Order.STABLE_ORDER),
+        /*outputs=*/ ImmutableSet.of(ActionInputHelper.fromPath(action.getXmlOutputPath())),
         SpawnAction.DEFAULT_RESOURCE_SET);
   }