Emit WGSL Break statement.

This CL adds emitting of the break statement to the WGSL writer.

Bug: tint:4
Change-Id: Iceae8cf8c1c77d63455621ea23f566af57c9e717
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/17163
Reviewed-by: David Neto <dneto@google.com>
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 9d55ca8..a77e480 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -408,6 +408,7 @@
     writer/wgsl/generator_impl_array_accessor_test.cc
     writer/wgsl/generator_impl_as_test.cc
     writer/wgsl/generator_impl_assign_test.cc
+    writer/wgsl/generator_impl_break_test.cc
     writer/wgsl/generator_impl_call_test.cc
     writer/wgsl/generator_impl_cast_test.cc
     writer/wgsl/generator_impl_entry_point_test.cc