HLSL: pass tessellation execution modes through to SPIR-V

The SPIR-V generator had assumed tessellation modes such as
primitive type and vertex order would only appear in tess eval
(domain) shaders.  SPIR-V allows either, and HLSL allows and
possibly requires them to be in the hull shader.

This change:

1. Passes them through for either tessellation stage, and,

2. Does not set up defaults in the domain stage for HLSl compilation,
to avoid conflicting definitions.

Test/baseResults/hlsl.hull.1.tesc.out

@@ -1,6 +1,7 @@
 hlsl.hull.1.tesc
 Shader version: 450
 vertices = 4
+vertex spacing = equal_spacing
 0:? Sequence
 0:26  Function Definition: @main(struct-VS_OUT-vf31[4];u1; ( temp structure{ temp 3-component vector of float cpoint})
 0:26    Function Parameters: 
@@ -115,6 +116,7 @@ Linked tessellation control stage:
 
 Shader version: 450
 vertices = 4
+vertex spacing = equal_spacing
 0:? Sequence
 0:26  Function Definition: @main(struct-VS_OUT-vf31[4];u1; ( temp structure{ temp 3-component vector of float cpoint})
 0:26    Function Parameters: 
@@ -232,6 +234,8 @@ vertices = 4
                               MemoryModel Logical GLSL450
                               EntryPoint TessellationControl 4  "main" 40 44 48 66 72 92
                               ExecutionMode 4 OutputVertices 4
+                              ExecutionMode 4 Isolines
+                              ExecutionMode 4 SpacingEqual
                               Name 4  "main"
                               Name 8  "VS_OUT"
                               MemberName 8(VS_OUT) 0  "cpoint"