Move private_manifest file insertion to jars merging phase.

By doing this, the change of private_manifest file won't trigger
Javac to re-run during re-build.

Bug: b/65455145
Test: m clean && m -j32
Change-Id: Ib90d56daf0be5f31b51e07b7714a933bc5cf4496
diff --git a/core/definitions.mk b/core/definitions.mk
index a19fc24..962c0f2 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -2269,12 +2269,7 @@
 $(if $(PRIVATE_JAR_EXCLUDE_PACKAGES), $(hide) rm -rf \
     $(foreach pkg, $(PRIVATE_JAR_EXCLUDE_PACKAGES), \
         $(PRIVATE_CLASS_INTERMEDIATES_DIR)/$(subst .,/,$(pkg))))
-$(if $(PRIVATE_JAR_MANIFEST), \
-    $(hide) sed -e "s/%BUILD_NUMBER%/$(BUILD_NUMBER_FROM_FILE)/" \
-            $(PRIVATE_JAR_MANIFEST) > $(dir $@)/manifest.mf && \
-        $(JAR) -cfm $@ $(dir $@)/manifest.mf, \
-    $(hide) $(JAR) -cf $@) \
-        $(call jar-args-sorted-files-in-directory,$(PRIVATE_CLASS_INTERMEDIATES_DIR))
+$(hide) $(JAR) -cf $@ $(call jar-args-sorted-files-in-directory,$(PRIVATE_CLASS_INTERMEDIATES_DIR))
 $(if $(PRIVATE_EXTRA_JAR_ARGS),$(call add-java-resources-to,$@))
 endef