Vulkan: Fix integer overflow for max per stage and combined uniform buffers. This was causing dEQP-GLES3.functional.implementation_limits.max_fragment_uniform_blocks and dEQP-GLES3.functional.implementation_limits.max_combined_uniform_blocks to fail on Vulkan drivers that expose > INT_MAX maxPerStageDescriptorUniformBuffers or maxDescriptorSetUniformBuffers limits. Bug: angleproject:3824 Change-Id: I6c5a328ddefa43fedb2361448fe4cbe6c405ef4e Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1734786 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>