Update all the HLSL tests that rely on HLSL 2018 (microsoft#4878)

This updates all the tests cases that rely on HLSL 2018 behaviors that
will break if the default HLSL version updates to 2021.

These tests are updated to be passed the HLSL 2018 version so they
continue testing and working under the same behaviors.

Author: llvm-beanz

tools/clang/test/CodeGenHLSL/Samples/D12/d12_multithreading_ps.hlsl

@@ -1,4 +1,4 @@
-// RUN: %dxc -E main -T ps_6_0 %s | FileCheck %s
+// RUN: %dxc -E main -T ps_6_0 -HV 2018 %s | FileCheck %s
 
 // CHECK: Sqrt
 // CHECK: dot3

tools/clang/test/CodeGenHLSL/Samples/D12/d12_multithreading_vs.hlsl

@@ -1,4 +1,4 @@
-// RUN: %dxc -E main -T vs_6_0 %s | FileCheck %s
+// RUN: %dxc -E main -T vs_6_0 -HV 2018 %s | FileCheck %s
 
 // The constant buffer should be allocated with ID zero and referenced as such.
 

tools/clang/test/CodeGenHLSL/Samples/DX11/BC6HDecode.hlsl

@@ -1,4 +1,4 @@
-// RUN: %dxc -E main -T cs_6_0 %s | FileCheck %s
+// RUN: %dxc -E main -T cs_6_0 -HV 2018 %s | FileCheck %s
 
 // CHECK: groupId
 // CHECK: flattenedThreadIdInGroup

tools/clang/test/CodeGenHLSL/Samples/DX11/BC6HEncode_EncodeBlockCS.hlsl

@@ -1,4 +1,4 @@
-// RUN: %dxc -E main -T cs_6_0 %s | FileCheck %s
+// RUN: %dxc -E main -T cs_6_0 -HV 2018 %s | FileCheck %s
 
 // check input.
 // CHECK: flattenedThreadIdInGroup

tools/clang/test/CodeGenHLSL/Samples/DX11/BC6HEncode_TryModeG10CS.hlsl

@@ -1,4 +1,4 @@
-// RUN: %dxc -E main -T cs_6_0 %s | FileCheck %s
+// RUN: %dxc -E main -T cs_6_0 -HV 2018 %s | FileCheck %s
 
 // check input.
 // CHECK: flattenedThreadIdInGroup

tools/clang/test/CodeGenHLSL/Samples/DX11/BC6HEncode_TryModeLE10CS.hlsl

@@ -1,4 +1,4 @@
-// RUN: %dxc -E main -T cs_6_0 %s | FileCheck %s
+// RUN: %dxc -E main -T cs_6_0 -HV 2018 %s | FileCheck %s
 
 // check input.
 // CHECK: flattenedThreadIdInGroup

tools/clang/test/CodeGenHLSL/Samples/DX11/ContactHardeningShadows11_PS.hlsl

@@ -1,4 +1,4 @@
-// RUN: %dxc -E main -T ps_6_0 -O0 %s | FileCheck %s
+// RUN: %dxc -E main -T ps_6_0 -O0 -HV 2018 %s | FileCheck %s
 
 // CHECK: Round_ni
 // CHECK: textureGather

tools/clang/test/CodeGenHLSL/Samples/DX11/DecalTessellation11_DS.hlsl

@@ -1,4 +1,4 @@
-// RUN: %dxc -E main -T ds_6_0 %s | FileCheck %s
+// RUN: %dxc -E main -T ds_6_0 -HV 2018 %s | FileCheck %s
 
 // CHECK: domainLocation
 // CHECK: domainLocation

tools/clang/test/CodeGenHLSL/Samples/DX11/TessellatorCS40_NumVerticesIndicesCS.hlsl

@@ -1,4 +1,4 @@
-// RUN: %dxc -E main -T cs_6_0 -O0 %s | FileCheck %s
+// RUN: %dxc -E main -T cs_6_0 -O0 -HV 2018 %s | FileCheck %s
 
 // CHECK: threadId
 // CHECK: bufferLoad

tools/clang/test/CodeGenHLSL/Samples/DX11/TessellatorCS40_TessellateIndicesCS.hlsl

@@ -1,4 +1,4 @@
-// RUN: %dxc -E main -T cs_6_0 -O0 %s | FileCheck %s
+// RUN: %dxc -E main -T cs_6_0 -O0 -HV 2018 %s | FileCheck %s
 
 // CHECK: threadId
 // CHECK: bufferLoad