reader/spirv: Remove debug spew

Change-Id: I2e3c9e681f2d33aaa83a27525e5e0f231f6a8973
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/50221
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: David Neto <dneto@google.com>
Commit-Queue: David Neto <dneto@google.com>
Auto-Submit: Ben Clayton <bclayton@google.com>

src/reader/spirv/parser_impl_module_var_test.cc

@@ -2144,7 +2144,6 @@ TEST_F(SpvModuleScopeVarParserTest, ScalarSpecConstant_UsedInFunction) {
      OpReturnValue %1
      OpFunctionEnd
   )" + MainBody();
-  std::cout << assembly << std::endl;
   auto p = parser(test::Assemble(assembly));
   ASSERT_TRUE(p->BuildAndParseInternalModuleExceptFunctions()) << p->error();
   auto fe = p->function_emitter(100);