build(ngc): run integration test hermetically

This ensures we run in a clean directory, using our real distribution. It finds bugs like @internal
APIs needed to type-check in the offline compiler, as well as problems in package.json.

Also move tsc-wrapped under tools/@angular

tools/@angular/tsc-wrapped/src/main.ts

@@ -0,0 +1,64 @@
+import * as fs from 'fs';
+import * as path from 'path';
+import * as ts from 'typescript';
+import {tsc, check} from './tsc';
+import NgOptions from './options';
+import {MetadataWriterHost, TsickleHost} from './compiler_host';
+
+export type CodegenExtension = (ngOptions: NgOptions, program: ts.Program, host: ts.CompilerHost) =>
+    Promise<any>;
+
+export function main(project: string, basePath?: string, codegen?: CodegenExtension): Promise<any> {
+  try {
+    let projectDir = project;
+    if (fs.lstatSync(project).isFile()) {
+      projectDir = path.dirname(project);
+    }
+    // file names in tsconfig are resolved relative to this absolute path
+    basePath = path.join(process.cwd(), basePath || projectDir);
+
+    // read the configuration options from wherever you store them
+    const {parsed, ngOptions} = tsc.readConfiguration(project, basePath);
+    ngOptions.basePath = basePath;
+
+    const host = ts.createCompilerHost(parsed.options, true);
+    const program = ts.createProgram(parsed.fileNames, parsed.options, host);
+    const errors = program.getOptionsDiagnostics();
+    check(errors);
+
+    if (ngOptions.skipTemplateCodegen || !codegen) {
+      codegen = () => Promise.resolve(null);
+    }
+    return codegen(ngOptions, program, host).then(() => {
+      tsc.typeCheck(host, program);
+
+      // Emit *.js with Decorators lowered to Annotations, and also *.js.map
+      const tsicklePreProcessor = new TsickleHost(host);
+      tsc.emit(tsicklePreProcessor, program);
+
+      if (!ngOptions.skipMetadataEmit) {
+        // Emit *.metadata.json and *.d.ts
+        // Not in the same emit pass with above, because tsickle erases
+        // decorators which we want to read or document.
+        // Do this emit second since TypeScript will create missing directories for us
+        // in the standard emit.
+        const metadataWriter = new MetadataWriterHost(host, program);
+        tsc.emit(metadataWriter, program);
+      }
+    });
+  } catch (e) {
+    return Promise.reject(e);
+  }
+}
+
+// CLI entry point
+if (require.main === module) {
+  const args = require('minimist')(process.argv.slice(2));
+  main(args.p || args.project || '.', args.basePath)
+      .then(exitCode => process.exit(exitCode))
+      .catch(e => {
+        console.error(e.stack);
+        console.error('Compilation failed');
+        process.exit(1);
+      });
+}