SF: Add IGBP list leak debugging info

Adds a few things intended to make debugging IGBP list leaks easier:
  1) A dumpsys line listing the current and max occupancies of the list
  2) A debug property to set the max: debug.sf.max_igbp_list_size
  3) Printing the current number of Layers when aborting

Since we still have an unknown leak, this also sets the default limit
four times higher to avoid hitting it in dogfood/automation.

Bug: 74616334
Test: Manual, set max to 100 and verify above behaviors
Change-Id: I7a6227a1d6fc05c197ec632db7dd9f875c64c6c9