Don't package host cross modules in javaFuzzPackager

Normally the host cross OS is windows, which only builds a few opted-in
modules.  When the host cross OS is set to linux_musl it builds all
modules that haven't explicitly opted out, producing linux_musl_common
variants of java modules.  Filter these out of javaFuzzPackager to
avoid conflicts with the linux_glibc_common modules.

Host cross common variants targets were missing the HostCross flag,
so also set it in getCommonTargets.

Bug: 236052820
Test: builds with linux_musl arm64 host cross enabled
Change-Id: I58c846076091bee7df50016c240a176c039c42e9

java/fuzz.go

@@ -171,6 +171,10 @@ func (s *javaFuzzPackager) GenerateBuildActions(ctx android.SingletonContext) {
 			return
 		}
 
+		if javaFuzzModule.Target().HostCross {
+			return
+		}
+
 		fuzzModuleValidator := fuzz.FuzzModule{
 			javaFuzzModule.ModuleBase,
 			javaFuzzModule.DefaultableModuleBase,