Add micro_bench to PRODUCT_PACKAGES_DEBUG

It's been converted to Soong, so can no longer use LOCAL_MODULE_TAGS. It
appears that some of the test runners expect to have it pre-installed.

Test: m; see it installed.
Change-Id: I189c9bbc2f2add90ac4f6841f4bf13852e4d579f
diff --git a/target/product/base.mk b/target/product/base.mk
index 919c16d..d6507c6 100644
--- a/target/product/base.mk
+++ b/target/product/base.mk
@@ -153,6 +153,7 @@
 PRODUCT_PACKAGES_DEBUG := \
     iotop \
     logpersist.start \
+    micro_bench \
     perfprofd \
     sqlite3 \
     strace