GLSL: add .expected.glsl files for all tests.

Bug: tint:1301
Change-Id: Id3a591a2fa0dfdb112046d5c57defbae07483e0d
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/69480
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>

test/statements/switch/common.wgsl.expected.glsl

@@ -0,0 +1,32 @@
+#version 310 es
+precision mediump float;
+
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+void f() {
+  int i = 0;
+  int result = 0;
+  switch(i) {
+    case 0: {
+      result = 10;
+      break;
+    }
+    case 1: {
+      result = 22;
+      break;
+    }
+    case 2: {
+      result = 33;
+      break;
+    }
+    default: {
+      result = 44;
+      break;
+    }
+  }
+  return;
+}
+void main() {
+  f();
+}
+
+

test/statements/switch/fallthrough.wgsl.expected.glsl

@@ -0,0 +1,21 @@
+#version 310 es
+precision mediump float;
+
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+void f() {
+  int i = 0;
+  switch(i) {
+    case 0: {
+      /* fallthrough */
+    }
+    default: {
+      break;
+    }
+  }
+  return;
+}
+void main() {
+  f();
+}
+
+

test/statements/switch/only_default_case.wgsl.expected.glsl

@@ -0,0 +1,20 @@
+#version 310 es
+precision mediump float;
+
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+void f() {
+  int i = 0;
+  int result = 0;
+  switch(i) {
+    default: {
+      result = 44;
+      break;
+    }
+  }
+  return;
+}
+void main() {
+  f();
+}
+
+