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

cc/binary.go

@@ -251,7 +251,7 @@ func (binary *binaryDecorator) linkerFlags(ctx ModuleContext, flags Flags) Flags
 				} else {
 					switch ctx.Os() {
 					case android.Android:
-						if ctx.bootstrap() && !ctx.inRecovery() && !ctx.inRamdisk() {
+						if ctx.bootstrap() && !ctx.inRecovery() && !ctx.inRamdisk() && !ctx.inVendorRamdisk() {
 							flags.DynamicLinker = "/system/bin/bootstrap/linker"
 						} else {
 							flags.DynamicLinker = "/system/bin/linker"
@@ -446,7 +446,8 @@ func (binary *binaryDecorator) install(ctx ModuleContext, file android.Path) {
 	// runtime APEX.
 	translatedArch := ctx.Target().NativeBridge == android.NativeBridgeEnabled
 	if InstallToBootstrap(ctx.baseModuleName(), ctx.Config()) && !ctx.Host() && ctx.directlyInAnyApex() &&
-		!translatedArch && ctx.apexVariationName() == "" && !ctx.inRamdisk() && !ctx.inRecovery() {
+		!translatedArch && ctx.apexVariationName() == "" && !ctx.inRamdisk() && !ctx.inRecovery() &&
+		!ctx.inVendorRamdisk() {
 
 		if ctx.Device() && isBionic(ctx.baseModuleName()) {
 			binary.installSymlinkToRuntimeApex(ctx, file)