Treat RUNFILES_TREE_MARKER as a directory in BuildEvent.forArtifact().

952aabb didn't fix #28330 because `BuildEvent.forArtifact()` (sometimes?) sees a `FileArtifactValue.RUNFILES_TREE_MARKER`, not a `RunfilesProxyArtifactValue`.

Fixes #28330.

PiperOrigin-RevId: 884388938
Change-Id: Ic5be6a83479d5afefd4a25a5b83049a2fe7b0244

Author: tjgq

src/main/java/com/google/devtools/build/lib/buildeventstream/BuildEvent.java

@@ -14,6 +14,8 @@
 
 package com.google.devtools.build.lib.buildeventstream;
 
+import static com.google.devtools.build.lib.actions.FileArtifactValue.RUNFILES_TREE_MARKER;
+
 import com.google.common.base.MoreObjects;
 import com.google.common.base.Objects;
 import com.google.common.base.Preconditions;
@@ -73,6 +75,11 @@ public boolean isOutput() {
       public static LocalFileType forArtifact(
           Artifact artifact, @Nullable FileArtifactValue metadata) {
         if (metadata != null) {
+          if (metadata.equals(RUNFILES_TREE_MARKER)) {
+            // TODO(tjgq): Remove RUNFILES_TREE_MARKER in favor of RunfilesProxyArtifactValue,
+            // which would make this special case unnecessary.
+            return LocalFileType.OUTPUT_DIRECTORY;
+          }
           return switch (metadata.getType()) {
             case DIRECTORY -> LocalFileType.OUTPUT_DIRECTORY;
             case SYMLINK -> LocalFileType.OUTPUT_SYMLINK;