Print only literal values when printing literals (#2469)

Current `<<` operator on `Literal` prints `[type].const` with it. But
`[type].const` is rather an instruction than a literal itself, and
printing it with the literals makes less sense when we later have
literals whose type don't have `const` instructions (such as reference
types).

This patch
- Makes `<<` operator on `Literal` print only its value
- Makes wasm-shell's shell interface comply with the spec interpreter's
  printing format (`value : type`).
- Prints wasm-shell's `[trap]` message to stderr

These make all `fix_` routines for spec tests in check.py unnecessary.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/shell-interface.h b/src/shell-interface.h
index 72c7dc67b..71e09189d 100644
--- a/src/shell-interface.h
+++ b/src/shell-interface.h
@@ -135,7 +135,7 @@ struct ShellExternalInterface : ModuleInstance::ExternalInterface {
   Literal callImport(Function* import, LiteralList& arguments) override {
     if (import->module == SPECTEST && import->base == PRINT) {
       for (auto argument : arguments) {
-        std::cout << '(' << argument << ')' << '\n';
+        std::cout << argument << " : " << argument.type << '\n';
       }
       return Literal();
     } else if (import->module == ENV && import->base == EXIT) {
@@ -211,7 +211,7 @@ struct ShellExternalInterface : ModuleInstance::ExternalInterface {
   }
 
   void trap(const char* why) override {
-    std::cout << "[trap " << why << "]\n";
+    std::cerr << "[trap " << why << "]\n";
     throw TrapException();
   }
 };