ART: Fix missing \ in Android.gtest.mk

Follow-up to commit 28fd62af6fcce33c83488e1f0e5876c1cdab8f15

Test: m test-art-host-gtest
Change-Id: I6b879f8372e27c18273aa1e23756388a94d4a233
diff --git a/build/Android.gtest.mk b/build/Android.gtest.mk
index 468eec6..11ebc2f 100644
--- a/build/Android.gtest.mk
+++ b/build/Android.gtest.mk
@@ -543,7 +543,7 @@
 # under ASAN.
 $$(gtest_output): $$(gtest_exe) $$(gtest_deps)
 	$(hide) ($$(call ART_TEST_SKIP,$$(NAME)) && set -o pipefail && \
-		ASAN_OPTIONS=detect_leaks=1 timeout -k 120s -s SIGRTMIN+2 3600s
+		ASAN_OPTIONS=detect_leaks=1 timeout -k 120s -s SIGRTMIN+2 3600s \
 			$(HOST_OUT_EXECUTABLES)/timeout_dumper \
 				$$< --gtest_output=xml:$$@ 2>&1 | tee $$<.tmp.out >&2 && \
 		{ $$(call ART_TEST_PASSED,$$(NAME)) ; rm $$<.tmp.out ; }) || \