FTL: Add StaticVector<T, N>

FTL is a template library shared by SurfaceFlinger and InputFlinger.

StaticVector is a hybrid of std::array and std::vector, a statically
allocated container with fixed capacity. It will serve as a base for
SmallVector and SmallMap.

Bug: 160012986
Test: ftl_test
Test: Apply ag/12919186 and compare assembly
Change-Id: I821c736f3411e970402faf19d9238b68c056ca93