[RenderEngine] Add cache contents to dumpsys

We've had some high EGL utilization attributed to SurfaceFlinger
recently, so adding info to dumpsys to hopefully catch a leak.

Bug: 137514000
Test: dumpsys
Change-Id: I38ccebda5db9847c6c526d4df5a97bc6394325a9
Merged-In: I22cf9eb01162d341c44dbe1440f74865dbf960fb
2 files changed