Use the new sdk/build/tools.atree.

As the sdk.git project is branched differently from the rest
of the platform, it's important to be able to control what
goes in the tools folder of the SDK on a per-branch basis.

Right now development/build/sdk.atree control what goes in
the tools folder (coming almost only from sdk.git) which causes
problems when the development.git and sdk.git branches are not
in sync.

Change-Id: I9158501cd68783d593e49e5fdea7f17d19b0120f

core/Makefile

@@ -1279,7 +1279,8 @@ atree_dir := development/build
 sdk_atree_files := \
 	$(atree_dir)/sdk.exclude.atree \
 	$(atree_dir)/sdk.atree \
-	$(atree_dir)/sdk-$(HOST_OS)-$(HOST_ARCH).atree
+	$(atree_dir)/sdk-$(HOST_OS)-$(HOST_ARCH).atree \
+	sdk/build/tools.atree
 
 deps := \
 	$(target_notice_file_txt) \
@@ -1293,6 +1294,7 @@ deps := \
 	$(INSTALLED_BUILD_PROP_TARGET) \
 	$(ATREE_FILES) \
 	$(atree_dir)/sdk.atree \
+	sdk/build/tools.atree \
 	$(HOST_OUT_EXECUTABLES)/atree \
     $(HOST_OUT_EXECUTABLES)/line_endings