Modifies CodeGenSimpleHS 10 and 11 so that they use target hs_6_0 (#766)

tools/clang/test/CodeGenHLSL/SimpleHs10.hlsl

@@ -1,4 +1,4 @@
-// RUN: %dxc -E main -T hs_6_1  %s 2>&1 | StdErrCheck %s
+// RUN: %dxc -E main -T hs_6_0  %s 2>&1 | StdErrCheck %s
 
 // Same as SimpleHS11.hlsl, except that we only verify StdErr for the warning
 // message.

tools/clang/test/CodeGenHLSL/SimpleHs11.hlsl

@@ -1,4 +1,4 @@
-// RUN: %dxc -E main -T hs_6_1  %s 2>&1 | FileCheck %s
+// RUN: %dxc -E main -T hs_6_0  %s 2>&1 | FileCheck %s
 
 // Same as SimpleHS10.hlsl, except that now we check that the compiler didn't
 // lie when it told us which overload it selected.