Revert "Delete "background process limit" debug option"

This reverts commit c163eb07cea8b414c74d0784b9979dfd65786857.

Reason for revert: we did a 180 on MCP deprecation, see b/345628418

Change-Id: I2bd2dd7b8fa5275fa81f75d47919ac70d721cd72
4 files changed