[sksl] Emit SPIR-V 1.3

Bump the SPIR-V version emitted by SkSL from 1.0 to 1.3. SPIR-V 1.3 is
the newest version Vulkan 1.1 (Skia's minimum) is required to accept,
and the first version with GroupNonUniform (subgroup) operations.

The SPIRV-Tools target environment used for validation (SkSL validator,
skslc golden disassembly, and viewer) moves from SPV_ENV_VULKAN_1_0 to
SPV_ENV_VULKAN_1_1 accordingly.

Storage buffers still use Uniform + BufferBlock, which is deprecated but
valid through SPIR-V 1.3. No change in generated golden output.

Clients must create their VkInstance with apiVersion >= 1.1 and set

VulkanBackendContext::fMaxAPIVersion to match; see the release note.
Change-Id: Ifa6d0853e8035f58142d1ba0afe573cd1c9b9823
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/1378479
Reviewed-by: Nathan Sanchez <nathanasanchez@google.com>
Commit-Queue: Thomas Smith <thomsmit@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>