Use hermetic `strip` for atree

Use the newly exposed HOST_STRIP from Soong to strip host tools during
atree.

This appears to produce slightly different host tools, but they're still
stripped.

Test: m PRODUCT-sdk_arm64-sdk dist sdk_repo
Change-Id: Id2863347882eb63d2a4cce45f0cd8de510ed4543
diff --git a/core/Makefile b/core/Makefile
index 252bd22..8c54470 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -3233,7 +3233,7 @@
 	if [ $$FAIL ]; then exit 1; fi
 	$(hide) echo $(notdir $(SDK_FONT_DEPS)) | tr " " "\n"  > $(SDK_FONT_TEMP)/fontsInSdk.txt
 	$(hide) ( \
-		ATREE_STRIP="strip -x" \
+		ATREE_STRIP="$(HOST_STRIP) -x" \
 		$(HOST_OUT_EXECUTABLES)/atree \
 		$(addprefix -f ,$(PRIVATE_INPUT_FILES)) \
 			-m $(PRIVATE_DEP_FILE) \