Remove adb from host build in buildbot.

HOST_PREFER_32_BIT is for ART use only.

Change-Id: I080de289d22ed9ad9ab6befbd0605ef4043e8b15
diff --git a/tools/buildbot-build.sh b/tools/buildbot-build.sh
index c69b819..21eec9b 100755
--- a/tools/buildbot-build.sh
+++ b/tools/buildbot-build.sh
@@ -19,7 +19,7 @@
   exit 1
 fi
 
-common_targets="vogar vogar.jar core-tests apache-harmony-jdwp-tests-hostdex out/host/linux-x86/bin/adb jsr166-tests"
+common_targets="vogar vogar.jar core-tests apache-harmony-jdwp-tests-hostdex jsr166-tests"
 android_root="/data/local/tmp/system"
 linker="linker"
 mode="target"
@@ -64,7 +64,7 @@
 done
 
 if [[ $mode == "host" ]]; then
-  make_command="make $j_arg build-art-host-tests $common_targets out/host/linux-x86/lib/libjavacoretests.so out/host/linux-x86/lib64/libjavacoretests.so"
+  make_command="make $j_arg build-art-host-tests $common_targets out/host/linux-x86/lib/libjavacoretests.so out/host/linux-x86/lib64/libjavacoretests.so out/host/linux-x86/bin/adb"
   echo "Executing $make_command"
   $make_command
 elif [[ $mode == "target" ]]; then