Provide access to product_variables.malloc_svelte.cflags inside target.

Test: soong still works.

Change-Id: I359f1e750e5961a21e3eeb9f1f3aa47974d7e99f
diff --git a/android/variable.go b/android/variable.go
index b4ed1b7..b478389 100644
--- a/android/variable.go
+++ b/android/variable.go
@@ -43,8 +43,8 @@
 		} `android:"arch_variant"`
 
 		Malloc_not_svelte struct {
-			Cflags []string
-		}
+			Cflags []string `android:"arch_variant"`
+		} `android:"arch_variant"`
 
 		Safestack struct {
 			Cflags []string `android:"arch_variant"`