Copy generated xml file for NDK api coverage to dist when CLANG_COVERAGE flag set.

Test: build/soong/soong_ui.bash --make-mode SKIP_ABI_CHECKS=true TARGET_PRODUCT=aosp_cf_x86_phone TARGET_BUILD_VARIANT=userdebug droid dist DIST_DIR=/usr/local/google/home/sophiez/my_dist_dir EMMA_INSTRUMENT=true EMMA_INSTRUMENT_FRAMEWORK=true CLANG_COVERAGE=true SKIP_BOOT_JARS_CHECK=true tests

Change-Id: I778da9ca7897752274744eca5530412c146fac96
diff --git a/core/main.mk b/core/main.mk
index 5d2ec7c..2b59c07 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -1665,6 +1665,11 @@
   $(call dist-for-goals, dist_files, $(api_xmls))
   api_xmls :=
 
+  ifdef CLANG_COVERAGE
+    $(foreach f,$(SOONG_NDK_API_XML), \
+        $(call dist-for-goals,droidcore,$(f):ndk_coverage_xml_dir/$(notdir $(f))))
+  endif
+
 # Building a full system-- the default is to build droidcore
 droid_targets: droidcore dist_files