We've had several issues with shader caches which are only implemented
on Android which makes them challenging to debug.
The existing BlobCache object has a default implementation that is
disabled by default. When debug layers are enabled resize the default
cache so that it gets used and provides behavior closer to Android.
This caching will be enabled when debug layers are enabled, e.g.
EGL_PLATFORM_ANGLE_DEBUG_LAYERS_ENABLED_ANGLE attribute is true.
This is done for angle_end2end_tests and deqp tests.

Reland after bugfix angleproject:4535

Bug: b:152292873
Bug: angleproject:4535
Change-Id: Icefa8c55e39985d653d8d8a8bc8c734210025b50
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2134449Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Courtney Goeltzenleuchter <courtneygo@google.com>