Skylark: Implemented ctx.expand_location() which expands the location(s) of the target file(s) of labels

--
MOS_MIGRATED_REVID=97949264
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/CommandHelper.java b/src/main/java/com/google/devtools/build/lib/analysis/CommandHelper.java
index 5075aba..382c21a 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/CommandHelper.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/CommandHelper.java
@@ -167,10 +167,12 @@
    * variables.
    */
   @SkylarkCallable(doc = "Experimental.")
-  public String resolveCommandAndExpandLabels(Boolean supportLegacyExpansion,
-      Boolean allowDataInLabel) {
+  public String resolveCommandAndExpandLabels(
+      Boolean supportLegacyExpansion, Boolean allowDataInLabel) {
     String command = ruleContext.attributes().get("cmd", Type.STRING);
-    command = new LocationExpander(ruleContext, labelMap, allowDataInLabel).expand("cmd", command);
+    command =
+        new LocationExpander(ruleContext, labelMap, allowDataInLabel)
+            .expandAttribute("cmd", command);
 
     if (supportLegacyExpansion) {
       command = expandLabels(command, labelMap);