Use new metalava jar-to-diff command

Replaces the use of `--input-jar-file` and `--api-xml` with the newly
added `jar-to-diff` command.

Test: TARGETS=$(for i in api.xml system-api.xml module-lib-api.xml system-server-api.xml test-api.xml; do echo out/target/common/obj/$i; done)
      m $TARGETS
      # Diff $TARGETS with and without this change to make sure that
      # they are identical, which they are.
Change-Id: I6a78febb4b2e4d06a0b3aea29fb4a7f94c9ab9a4
diff --git a/core/main.mk b/core/main.mk
index b798b49..d732e30 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -1908,7 +1908,7 @@
   $(api_xmls):
 	$(hide) echo "Converting API file to XML: $@"
 	$(hide) mkdir -p $(dir $@)
-	$(hide) $(APICHECK_COMMAND) --input-api-jar $< --api-xml $@
+	$(hide) $(APICHECK_COMMAND) jar-to-jdiff $< $@
 
   $(foreach xml,$(sort $(api_xmls)),$(call declare-1p-target,$(xml),))