Revert "Change UnrefDDLTask to just be the DDLTask"

This CL reverts the following 3 CLs due to coupled perf and memory regressions:

88e8bb2 https://skia-review.googlesource.com/c/skia/+/333576 (Fix UMR (valgrind) bug in GrDrawingManager)
cca1976 https://skia-review.googlesource.com/c/skia/+/333463 (Remove the bulk add-renderTasks entry point from the drawing manager)
02dd0ed https://skia-review.googlesource.com/c/skia/+/332600 (Change UnrefDDLTask to just be the DDLTask)

Bug: 1147659, 1147634, 1147650, skia:10936
Change-Id: I937d656c4126eac954a9d7930a4034488d6ef5df
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/334061
Reviewed-by: Adlai Holler <adlai@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
14 files changed