While getting NBA2K20 MEC to work, discovered that
SetupContext was so large, it was causing a stack
overflow. To fix, simply break up the function into
a series of helpers if the number of calls exceeds
a set limit.

Test: NBA2K20 MEC
Bug: b/160014453
Bug: angleproject:4048
Change-Id: I332d5dea5fc4e14700b68150cbe31a4c88cdae89
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2321739Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Manh Nguyen <nguyenmh@google.com>
Commit-Queue: Cody Northrop <cnorthrop@google.com>