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
diff --git a/android/arch.go b/android/arch.go
index 382a7df..e72614c 100644
--- a/android/arch.go
+++ b/android/arch.go
@@ -1825,7 +1825,9 @@
 	for _, t := range targets {
 		if _, found := set[t.Os.String()]; !found {
 			set[t.Os.String()] = true
-			ret = append(ret, commonTargetMap[t.Os.String()])
+			common := commonTargetMap[t.Os.String()]
+			common.HostCross = t.HostCross
+			ret = append(ret, common)
 		}
 	}
 
diff --git a/java/fuzz.go b/java/fuzz.go
index b306991..d0f369f 100644
--- a/java/fuzz.go
+++ b/java/fuzz.go
@@ -171,6 +171,10 @@
 			return
 		}
 
+		if javaFuzzModule.Target().HostCross {
+			return
+		}
+
 		fuzzModuleValidator := fuzz.FuzzModule{
 			javaFuzzModule.ModuleBase,
 			javaFuzzModule.DefaultableModuleBase,