SpirvShader: Implement GLSLstd450Sqrt
SpirvShader: Implement GLSLstd450Sqrt

Bug: b/126873455
Tests: dEQP-VK.glsl.builtin.precision.sqrt.*
Change-Id: Ia178618bb2777d9b58beef19d4e18767cc9a8f73
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/28695
Tested-by: Ben Clayton <1f693eb7158dc33015048c09d6712f74dabddf79@google.com>
Reviewed-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>
Kokoro-Presubmit: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>

bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader,google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader