Reland "Create a pool of 20 measurement files per library for coverage."

This reverts commit 0c4fb3dd4bade98d8da17129ec7c278be4f4e28f.

Reason for revert: Permissions issue in b/173448692 are fixed.

Change-Id: Ic0382484c8e46470b4d7986681229fef0f0dcdfc
diff --git a/rootdir/Android.mk b/rootdir/Android.mk
index 2bceb75..c4c8768 100644
--- a/rootdir/Android.mk
+++ b/rootdir/Android.mk
@@ -69,7 +69,7 @@
 
 EXPORT_GLOBAL_CLANG_COVERAGE_OPTIONS :=
 ifeq ($(CLANG_COVERAGE),true)
-  EXPORT_GLOBAL_CLANG_COVERAGE_OPTIONS := export LLVM_PROFILE_FILE /data/misc/trace/clang-%p-%m.profraw
+  EXPORT_GLOBAL_CLANG_COVERAGE_OPTIONS := export LLVM_PROFILE_FILE /data/misc/trace/clang-%20m.profraw
 endif
 
 # Put it here instead of in init.rc module definition,