raise class region size to 32GB for arm64 Android

Android.bp

@@ -26,6 +26,7 @@ common_cflags = [
     "-DREGION_QUARANTINE_QUEUE_LENGTH=1024",
     "-DREGION_QUARANTINE_SKIP_THRESHOLD=33554432", // 32MiB
     "-DFREE_SLABS_QUARANTINE_RANDOM_LENGTH=32",
+    "-DCONFIG_CLASS_REGION_SIZE=34359738368", // 32GiB
     "-DN_ARENA=1",
     "-DCONFIG_STATS=true",
 ]
@@ -34,14 +35,6 @@ cc_defaults {
     name: "hardened_malloc_defaults",
     defaults: ["linux_bionic_supported"],
     cflags: common_cflags,
-    arch: {
-        arm64: {
-            cflags: ["-DCONFIG_CLASS_REGION_SIZE=2147483648"] // 2GiB
-        },
-        x86_64: {
-            cflags: ["-DCONFIG_CLASS_REGION_SIZE=34359738368"] // 32GiB
-        },
-    },
     conlyflags: ["-std=c17", "-Wmissing-prototypes"],
     stl: "none",
 }