SPV: Fix #1575, fix #1593: Support HLSL #line

SPIR-V OpLines now contain filenames from HLSL-style #lines.

Test/hlsl.pp.line3.frag

@@ -0,0 +1,34 @@
+Texture2D g_tColor[ 128 ] ;
+
+layout (push_constant) cbuffer PerViewConstantBuffer_t
+{
+    uint g_nDataIdx;
+    uint g_nDataIdx2;
+    bool g_B;
+} ;
+
+SamplerState g_sAniso;
+
+struct PS_INPUT
+{
+    float2 vTextureCoords : TEXCOORD2 ;
+} ;
+
+struct PS_OUTPUT
+{
+    float4 vColor : SV_Target0 ;
+} ;
+
+PS_OUTPUT MainPs ( PS_INPUT i )
+{
+    PS_OUTPUT ps_output ;
+   
+    uint u;
+    if (g_B)
+#include "i1.h"
+    else
+        u = g_nDataIdx2;
+    ps_output . vColor = g_tColor [ u ] . Sample ( g_sAniso , i . vTextureCoords . xy );
+    return ps_output ;
+}
+