bootclasspath_fragment: Always output contents property in snapshot

Bug: 177892522
Test: m art-module-sdk
      - check generated snapshot contains contents property
Change-Id: I122dedba6600a199bfd83b01988da36ddfd09d63

java/bootclasspath_fragment.go

@@ -428,12 +428,7 @@ func (b *bootclasspathFragmentSdkMemberProperties) PopulateFromVariant(ctx andro
 	module := variant.(*BootclasspathFragmentModule)
 
 	b.Image_name = module.properties.Image_name
-	if b.Image_name == nil {
-		// Only one of image_name or contents can be specified. However, if image_name is set then the
-		// contents property is updated to match the configuration used to create the corresponding
-		// boot image. Therefore, contents property is only copied if the image name is not specified.
 	b.Contents = module.properties.Contents
-	}
 
 	// Get the flag file information from the module.
 	mctx := ctx.SdkModuleContext()

sdk/bootclasspath_fragment_sdk_test.go

@@ -113,6 +113,7 @@ prebuilt_bootclasspath_fragment {
     visibility: ["//visibility:public"],
     apex_available: ["com.android.art"],
     image_name: "art",
+    contents: ["mybootlib"],
 }
 
 java_import {
@@ -132,6 +133,7 @@ prebuilt_bootclasspath_fragment {
     visibility: ["//visibility:public"],
     apex_available: ["com.android.art"],
     image_name: "art",
+    contents: ["mysdk_mybootlib@current"],
 }
 
 java_import {