Use the lowest common denominator 32-bit abi for arm64 cts build.

So the 32-bit code can be run any supported 32-bit arm devices.

Bug: 18038310
Change-Id: Ie8864cfdb87a4759d1a775d43cb5316b1f022e2b
diff --git a/target/board/generic_arm64/BoardConfig.mk b/target/board/generic_arm64/BoardConfig.mk
index c57447d..818f857 100644
--- a/target/board/generic_arm64/BoardConfig.mk
+++ b/target/board/generic_arm64/BoardConfig.mk
@@ -25,13 +25,13 @@
 TARGET_2ND_CPU_ABI := armeabi-v7a
 TARGET_2ND_CPU_ABI2 := armeabi
 
-ifdef TARGET_BUILD_APPS
+ifneq ($(TARGET_BUILD_APPS)$(filter cts,$(MAKECMDGOALS)),)
 # DO NOT USE
 # DO NOT USE
 #
 # This architecture / CPU variant must NOT be used for any 64 bit
 # platform builds. It is the lowest common denominator required
-# to build an unbundled application for all supported 32 and 64 bit
+# to build an unbundled application or cts for all supported 32 and 64 bit
 # platforms.
 #
 # If you're building a 64 bit platform (and not an application) the
@@ -82,4 +82,3 @@
 BOARD_CACHEIMAGE_FILE_SYSTEM_TYPE := ext4
 BOARD_FLASH_BLOCK_SIZE := 512
 TARGET_USERIMAGES_SPARSE_EXT_DISABLED := true
-