Revert "Emit, even in the presence of declaration errors and noEmitOnError."

This reverts commit 19517ac0dd.

src/compiler/program.ts

@@ -87,6 +87,11 @@ module ts {
 
     export function getPreEmitDiagnostics(program: Program): Diagnostic[] {
         let diagnostics = program.getSyntacticDiagnostics().concat(program.getGlobalDiagnostics()).concat(program.getSemanticDiagnostics());
+
+        if (program.getCompilerOptions().declaration) {
+            diagnostics.concat(program.getDeclarationDiagnostics());
+        }
+
         return sortAndDeduplicateDiagnostics(diagnostics);
     }