No symlink for host APEXes

Symlinking doesn't make sense for host APEXes.

Bug: 150255435
Test: m com.android.art.host and inspect the built APEX; there is
no symlink.

Change-Id: I28492dfaaef471117a430be05255fbef76e557b0
diff --git a/apex/apex.go b/apex/apex.go
index 712afe4..992137a 100644
--- a/apex/apex.go
+++ b/apex/apex.go
@@ -2328,6 +2328,11 @@
 		a.linkToSystemLib = false
 	}
 
+	// We also don't want the optimization for host APEXes, because it doesn't make sense.
+	if ctx.Host() {
+		a.linkToSystemLib = false
+	}
+
 	// prepare apex_manifest.json
 	a.buildManifest(ctx, provideNativeLibs, requireNativeLibs)