HLSL: Add min*{float,int,uint} types

These HLSL types are guaranteed to have at least the given number of bits, but may have more.

min{16,10}float is mapped to EbtFloat at medium precision -> SPIRV RelaxedPrecision
min{16,12}int and min16uint are mapped to mediump -> SPIR-V RelaxedPrecision

gtests/Hlsl.FromFile.cpp

@@ -146,6 +146,7 @@ INSTANTIATE_TEST_CASE_P(
         {"hlsl.logical.unary.frag", "main"},
         {"hlsl.logical.binary.frag", "main"},
         {"hlsl.logical.binary.vec.frag", "main"},
+        {"hlsl.mintypes.frag", "main"},
         {"hlsl.multiEntry.vert", "RealEntrypoint"},
         {"hlsl.multiReturn.frag", "main"},
         {"hlsl.matrixindex.frag", "main"},