Add vendor-ramdisk image to Soong.

Add vendor_ramdisk_available and vendor_ramdisk attribute to
various rules. When a vendor_ramdisk variant of a module is
generated, it is installed to $OUT/vendor-ramdisk.

It is similar to a ramdisk image.
Test: m nothing -j

Change-Id: Ib2d16459f3094dbe21c3bdb7c016cb4b2bf62765
diff --git a/cc/fuzz.go b/cc/fuzz.go
index e81b40f..681e3bc 100644
--- a/cc/fuzz.go
+++ b/cc/fuzz.go
@@ -388,10 +388,10 @@
 			return
 		}
 
-		// Discard ramdisk + recovery modules, they're duplicates of
+		// Discard ramdisk + vendor_ramdisk + recovery modules, they're duplicates of
 		// fuzz targets we're going to package anyway.
 		if !ccModule.Enabled() || ccModule.Properties.PreventInstall ||
-			ccModule.InRamdisk() || ccModule.InRecovery() {
+			ccModule.InRamdisk() || ccModule.InVendorRamdisk() || ccModule.InRecovery() {
 			return
 		}