[ApiModel] Remove unused imports to make compilation succeed

Change-Id: I5852f3beef268c48b6a0016d220918796dbf8915
diff --git a/src/main/java/com/android/tools/r8/graph/DexProgramClass.java b/src/main/java/com/android/tools/r8/graph/DexProgramClass.java
index 25429fd..2bbb51b 100644
--- a/src/main/java/com/android/tools/r8/graph/DexProgramClass.java
+++ b/src/main/java/com/android/tools/r8/graph/DexProgramClass.java
@@ -8,8 +8,6 @@
 
 import com.android.tools.r8.ProgramResource;
 import com.android.tools.r8.ProgramResource.Kind;
-import com.android.tools.r8.androidapi.AndroidApiLevelCompute;
-import com.android.tools.r8.androidapi.ComputedApiLevel;
 import com.android.tools.r8.cf.CfVersion;
 import com.android.tools.r8.dex.IndexedItemCollection;
 import com.android.tools.r8.dex.MixedSectionCollection;