[tint] do not emit space for binding group 0

D3D11 only supports HLSL SM5.0 which doesn't support `space`
(binding group in WGSL). So for D3D11, only one binding group will be
used, and tint will not emit `space` for HLSL, so shaders can be used
with D3D11.

Bug: dawn:1705
Change-Id: Ie0e9868137f10762c5243e188d76f5e41879c2bc
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/125080
Commit-Queue: Peng Huang <penghuang@chromium.org>
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Ben Clayton <bclayton@google.com>
diff --git a/test/tint/array/assign_to_private_var.wgsl.expected.fxc.hlsl b/test/tint/array/assign_to_private_var.wgsl.expected.fxc.hlsl
index 6cf00a3..61083f2 100644
--- a/test/tint/array/assign_to_private_var.wgsl.expected.fxc.hlsl
+++ b/test/tint/array/assign_to_private_var.wgsl.expected.fxc.hlsl
@@ -9,10 +9,10 @@
 
 static int4 src_private[4] = (int4[4])0;
 groupshared int4 src_workgroup[4];
-cbuffer cbuffer_src_uniform : register(b0, space0) {
+cbuffer cbuffer_src_uniform : register(b0) {
   uint4 src_uniform[4];
 };
-RWByteAddressBuffer src_storage : register(u1, space0);
+RWByteAddressBuffer src_storage : register(u1);
 static int4 tint_symbol[4] = (int4[4])0;
 static int dst_nested[4][3][2] = (int[4][3][2])0;