Export variable for device sanitize arch to Soong

Also renames the variable from SANITIZE_ARCH to SANITIZE_TARGET_ARCH,
and makes it only apply to the device.

Bug: 29498013
Test: No change to build.ninja files with m -j SANITIZE_TARGET=address
Change-Id: Ib5f6ab448f5d96d2426c983308136670f9a55b7b
diff --git a/core/soong.mk b/core/soong.mk
index 1d42eb0..73622a2 100644
--- a/core/soong.mk
+++ b/core/soong.mk
@@ -48,6 +48,7 @@
 	echo '    "Allow_missing_dependencies": $(if $(TARGET_BUILD_APPS)$(filter true,$(SOONG_ALLOW_MISSING_DEPENDENCIES)),true,false),'; \
 	echo '    "SanitizeHost": [$(if $(SANITIZE_HOST),"$(subst $(space),"$(comma)",$(SANITIZE_HOST))")],'; \
 	echo '    "SanitizeDevice": [$(if $(SANITIZE_TARGET),"$(subst $(space),"$(comma)",$(SANITIZE_TARGET))")],'; \
+	echo '    "SanitizeDeviceArch": [$(if $(SANITIZE_TARGET_ARCH),"$(subst $(space),"$(comma)",$(SANITIZE_TARGET_ARCH))")],'; \
 	echo '    "HostStaticBinaries": $(if $(strip $(BUILD_HOST_static)),true,false),'; \
 	echo '    "Cpusets": $(if $(strip $(ENABLE_CPUSETS)),true,false),'; \
 	echo '    "Schedboost": $(if $(strip $(ENABLE_SCHEDBOOST)),true,false),'; \