Only print registered targets for `--version`

[dim]

Summary

In D33900, I added printing of the registered targets in clang's
PrintVersion function, which is not only used for --version output,
but also for -v (verbose mode) and -###. Especially the latter
seems to trip up some test cases, so it is probably better to only print
the registered targets for --version.

[nemanjai]

LGTM. This cleans up the failures on PPC (and probably SystemZ) so the bots should go back to green.

cfe/trunk/lib/Driver/Driver.cpp

if (Arg *A = C.getArgs().getLastArg(options::OPT_mthread_model)) {
     if (TC.isThreadModelSupported(A->getValue()))
       OS << "Thread model: " << A->getValue();
   } else
     OS << "Thread model: " << TC.getThreadModel();
   OS << '\n';
 
   // Print out the install directory.
   OS << "InstalledDir: " << InstalledDir << '\n';
-
-  // Print registered targets.
-  OS << '\n';
-  llvm::TargetRegistry::printRegisteredTargetsForVersion(OS);
 }
 
 /// PrintDiagnosticCategories - Implement the --print-diagnostic-categories
 /// option.
 static void PrintDiagnosticCategories(raw_ostream &OS) {
   // Skip the empty category.
   for (unsigned i = 1, max = DiagnosticIDs::getNumberOfCategories(); i != max;
        ++i)
if (C.getArgs().hasArg(options::OPT_help) ||
       C.getArgs().hasArg(options::OPT__help_hidden)) {
     PrintHelp(C.getArgs().hasArg(options::OPT__help_hidden));
     return false;
   }
 
   if (C.getArgs().hasArg(options::OPT__version)) {
     // Follow gcc behavior and use stdout for --version and stderr for -v.
     PrintVersion(C, llvm::outs());
+
+    // Print registered targets.
+    llvm::outs() << '\n';
+    llvm::TargetRegistry::printRegisteredTargetsForVersion(llvm::outs());
     return false;
   }
 
   if (C.getArgs().hasArg(options::OPT_v) ||
       C.getArgs().hasArg(options::OPT__HASH_HASH_HASH)) {
     PrintVersion(C, llvm::errs());
     SuppressMissingInputWarning = true;
   }