SPV_ENV_Vulkan_1_2 denotes support for all SPIR-V versions that are core
in Vulkan 1.2. This includes 1.4 and 1.5.

Tests: dEQP-VK.*
Bug: b/173046235
Change-Id: I7482d1bff6bf3b2c2291538517f6640647ab644c
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/50670Tested-by: Sean Risser <srisser@google.com>
Commit-Queue: Sean Risser <srisser@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>