Store VkPipelineCache to ShaderCache

Store vulkan pipeline cache in ShaderCache. Avoid writing to disk
unless pipeline cache size has changed or there was a new shader
compilation.

Test: Ran app startup test. Ran Calc app.
Bug: 122659224
Change-Id: Ie54ea8f0ee9c87387c310b369b2350310e20fa13
3 files changed