Remove the ability to install boot images by bootclasspath_fragments.

We don't need this anymore because we are going to compile ART jars and
framework jars together.

Bug: 280776428
Test: m
Change-Id: I070157530449a1bb5779e25984c367df3dde7b36
diff --git a/apex/prebuilt.go b/apex/prebuilt.go
index 31cecf1..0d83830 100644
--- a/apex/prebuilt.go
+++ b/apex/prebuilt.go
@@ -199,14 +199,11 @@
 				p.apexFilesForAndroidMk = append(p.apexFilesForAndroidMk, af)
 			}
 		} else if tag == exportedBootclasspathFragmentTag {
-			bcpfModule, ok := child.(*java.PrebuiltBootclasspathFragmentModule)
+			_, ok := child.(*java.PrebuiltBootclasspathFragmentModule)
 			if !ok {
 				ctx.PropertyErrorf("exported_bootclasspath_fragments", "%q is not a prebuilt_bootclasspath_fragment module", name)
 				return false
 			}
-			for _, makeModuleName := range bcpfModule.BootImageDeviceInstallMakeModules() {
-				p.requiredModuleNames = append(p.requiredModuleNames, makeModuleName)
-			}
 			// Visit the children of the bootclasspath_fragment.
 			return true
 		} else if tag == exportedSystemserverclasspathFragmentTag {