Use existing local for resolving const class

Change-Id: Idc7da28e57b7baf110210a104d226aa922e8d1dd
diff --git a/src/main/java/com/android/tools/r8/ir/optimize/ServiceLoaderRewriter.java b/src/main/java/com/android/tools/r8/ir/optimize/ServiceLoaderRewriter.java
index 1544263..6a55792 100644
--- a/src/main/java/com/android/tools/r8/ir/optimize/ServiceLoaderRewriter.java
+++ b/src/main/java/com/android/tools/r8/ir/optimize/ServiceLoaderRewriter.java
@@ -94,13 +94,7 @@
         continue;
       }
 
-      ConstClass constClass =
-          serviceLoaderLoad
-              .inValues()
-              .get(0)
-              .getAliasedValue()
-              .getConstInstruction()
-              .asConstClass();
+      ConstClass constClass = argument.getConstInstruction().asConstClass();
 
       // Check that the service is not kept.
       if (appView.appInfo().isPinned(constClass.getValue())) {