Build: Add option to restrict sanitization by architecture

Add Make variable SANITIZE_ARCH to selectively sanitize binaries.
This uses the "bitness," i.e., 32 or 64, to potentially filter
the sanitization. By default, both are being sanitized.

This can be used to create builds that lower the sanitization
burden by not sanitizing "half" of the platform.

Bug: 29498013
Change-Id: I73e6d479f08a970ba912f4f63967d32f3487125f
diff --git a/core/config_sanitizers.mk b/core/config_sanitizers.mk
index 6e96880..524a065 100644
--- a/core/config_sanitizers.mk
+++ b/core/config_sanitizers.mk
@@ -24,6 +24,12 @@
   my_sanitize := $(my_global_sanitize)
 endif
 
+# Add a filter point for 32-bit vs 64-bit sanitization (to lighten the burden).
+SANITIZE_ARCH ?= 32 64
+ifeq ($(filter $(SANITIZE_ARCH),$(my_32_64_bit_suffix)),)
+  my_sanitize :=
+endif
+
 # Don't apply sanitizers to NDK code.
 ifdef LOCAL_SDK_VERSION
   my_sanitize :=