tint/transform: Include diagnostics in TINT_PRINT_PROGRAM_FOR_EACH_TRANSFORM

Change-Id: Id3e7e0cce464e8b1db00c2adab8db350eee0168c
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/111041
Reviewed-by: James Price <jrprice@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
diff --git a/src/tint/transform/manager.cc b/src/tint/transform/manager.cc
index d680cb6..f93c5d7 100644
--- a/src/tint/transform/manager.cc
+++ b/src/tint/transform/manager.cc
@@ -37,11 +37,15 @@
 #if TINT_PRINT_PROGRAM_FOR_EACH_TRANSFORM
     auto print_program = [&](const char* msg, const Transform* transform) {
         auto wgsl = Program::printer(program);
-        std::cout << "---------------------------------------------------------" << std::endl;
-        std::cout << "-- " << msg << " " << transform->TypeInfo().name << ":" << std::endl;
-        std::cout << "---------------------------------------------------------" << std::endl;
+        std::cout << "=========================================================" << std::endl;
+        std::cout << "== " << msg << " " << transform->TypeInfo().name << ":" << std::endl;
+        std::cout << "=========================================================" << std::endl;
         std::cout << wgsl << std::endl;
-        std::cout << "---------------------------------------------------------" << std::endl
+        if (!program->IsValid()) {
+            std::cout << "-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --" << std::endl;
+            std::cout << program->Diagnostics().str() << std::endl;
+        }
+        std::cout << "=========================================================" << std::endl
                   << std::endl;
     };
 #endif