HLSL: Move debug naming to a simpler, more consistent, scheme.

This will help in expanding flattening and reducing splitting.
diff --git a/Test/baseResults/hlsl.rw.vec2.bracket.frag.out b/Test/baseResults/hlsl.rw.vec2.bracket.frag.out
index afcc52a..d920bf3 100644
--- a/Test/baseResults/hlsl.rw.vec2.bracket.frag.out
+++ b/Test/baseResults/hlsl.rw.vec2.bracket.frag.out
@@ -826,7 +826,7 @@
 0:?     Sequence
 0:53      Sequence
 0:53        move second child to first child ( temp 4-component vector of float)
-0:?           'Color' (layout( location=0) out 4-component vector of float)
+0:?           '@entryPointOutput.Color' (layout( location=0) out 4-component vector of float)
 0:53          Color: direct index for structure ( temp 4-component vector of float)
 0:53            Function Call: @main( ( temp structure{ temp 4-component vector of float Color})
 0:53            Constant:
@@ -849,7 +849,7 @@
 0:?     'g_tTex2di2a' (layout( rg32i) uniform iimage2DArray)
 0:?     'g_tTex2du2a' (layout( rg32ui) uniform uimage2DArray)
 0:?     'anon@0' (layout( row_major std140) uniform block{ uniform int c1,  uniform 2-component vector of int c2,  uniform 3-component vector of int c3,  uniform 4-component vector of int c4,  uniform int o1,  uniform 2-component vector of int o2,  uniform 3-component vector of int o3,  uniform 4-component vector of int o4,  uniform 2-component vector of float uf2,  uniform 2-component vector of int ui2,  uniform 2-component vector of uint uu2})
-0:?     'Color' (layout( location=0) out 4-component vector of float)
+0:?     '@entryPointOutput.Color' (layout( location=0) out 4-component vector of float)
 
 
 Linked fragment stage:
@@ -1682,7 +1682,7 @@
 0:?     Sequence
 0:53      Sequence
 0:53        move second child to first child ( temp 4-component vector of float)
-0:?           'Color' (layout( location=0) out 4-component vector of float)
+0:?           '@entryPointOutput.Color' (layout( location=0) out 4-component vector of float)
 0:53          Color: direct index for structure ( temp 4-component vector of float)
 0:53            Function Call: @main( ( temp structure{ temp 4-component vector of float Color})
 0:53            Constant:
@@ -1705,7 +1705,7 @@
 0:?     'g_tTex2di2a' (layout( rg32i) uniform iimage2DArray)
 0:?     'g_tTex2du2a' (layout( rg32ui) uniform uimage2DArray)
 0:?     'anon@0' (layout( row_major std140) uniform block{ uniform int c1,  uniform 2-component vector of int c2,  uniform 3-component vector of int c3,  uniform 4-component vector of int c4,  uniform int o1,  uniform 2-component vector of int o2,  uniform 3-component vector of int o3,  uniform 4-component vector of int o4,  uniform 2-component vector of float uf2,  uniform 2-component vector of int ui2,  uniform 2-component vector of uint uu2})
-0:?     'Color' (layout( location=0) out 4-component vector of float)
+0:?     '@entryPointOutput.Color' (layout( location=0) out 4-component vector of float)
 
 // Module Version 10000
 // Generated by (magic number): 80001
@@ -1837,7 +1837,7 @@
                               Name 557  "storeTempPost"
                               Name 565  "storeTemp"
                               Name 573  "psout"
-                              Name 581  "Color"
+                              Name 581  "@entryPointOutput.Color"
                               Name 586  "g_sSamp"
                               Name 589  "g_tTex1df2a"
                               Name 592  "g_tTex1di2a"
@@ -1867,7 +1867,7 @@
                               Decorate 130(g_tTex3df2) DescriptorSet 0
                               Decorate 140(g_tTex3di2) DescriptorSet 0
                               Decorate 148(g_tTex3du2) DescriptorSet 0
-                              Decorate 581(Color) Location 0
+                              Decorate 581(@entryPointOutput.Color) Location 0
                               Decorate 586(g_sSamp) DescriptorSet 0
                               Decorate 586(g_sSamp) Binding 0
                               Decorate 589(g_tTex1df2a) DescriptorSet 0
@@ -1967,7 +1967,7 @@
              574:   42(fvec4) ConstantComposite 404 404 404 404
              575:             TypePointer Function 42(fvec4)
              580:             TypePointer Output 42(fvec4)
-      581(Color):    580(ptr) Variable Output
+581(@entryPointOutput.Color):    580(ptr) Variable Output
              584:             TypeSampler
              585:             TypePointer UniformConstant 584
     586(g_sSamp):    585(ptr) Variable UniformConstant
@@ -1993,7 +1993,7 @@
                5:             Label
              582:43(PS_OUTPUT) FunctionCall 45(@main()
              583:   42(fvec4) CompositeExtract 582 0
-                              Store 581(Color) 583
+                              Store 581(@entryPointOutput.Color) 583
                               Return
                               FunctionEnd
     11(Fn1(vi2;):    7(ivec2) Function None 9