Return false in DirectlyInAnyApex for host libraries.

Host doesn't have apexes.

Bug: 122947954
Test: build dex2oat, check that libnativebridge is installed.
Change-Id: I3548e3f155a200e56d71e88631b71511bad84161
diff --git a/android/apex.go b/android/apex.go
index 8d99d56..a93baf6 100644
--- a/android/apex.go
+++ b/android/apex.go
@@ -178,8 +178,16 @@
 	return false
 }
 
+type hostContext interface {
+	Host() bool
+}
+
 // Tests whether a module named moduleName is directly depended on by any APEX.
-func DirectlyInAnyApex(moduleName string) bool {
+func DirectlyInAnyApex(ctx hostContext, moduleName string) bool {
+	if ctx.Host() {
+		// Host has no APEX.
+		return false
+	}
 	apexNamesMapMutex.Lock()
 	defer apexNamesMapMutex.Unlock()
 	if apexNames, ok := apexNamesMap()[moduleName]; ok {