flounder: make aosp_flounder a 64-bit build

aosp_flounder is now a 64-bit multilib build.  aosp_flounder64 is
an alias for aosp_flounder.  aosp_flounder32 is a pure 32-bit build.

Change-Id: I909bff1dc67032c1882d273699f7277dfda29a48
diff --git a/CleanSpec.mk b/CleanSpec.mk
index 8fc34b7..863e4b1 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -49,3 +49,5 @@
 $(call add-clean-step, rm -rf $(OUT_DIR)/buildcache/aosp_flounder)
 $(call add-clean-step, rm -rf $(OUT_DIR)/target/product/flounder)
 $(call add-clean-step, rm -rf $(OUT_DIR)/buildcache/aosp_flounder)
+$(call add-clean-step, rm -rf $(OUT_DIR)/target/product/flounder)
+$(call add-clean-step, rm -rf $(OUT_DIR)/buildcache/aosp_flounder)