build: ensure script that build the Zone.js package can be run from any directory (#39455)

The scripts that build the Angular and Zone.js NPM packages rely on
absolute paths in order to work correctly regardless of what the current
working directory is when the scripts are invoked. However, the
`npm pack` command executed in the `zone-js-builder.js` script outputs
the generated `.tgz` archive in the current working directory. This
causes the script to fail when invoked for any working directory other
than the project root directory.

This commit fixes this by ensuring the `npm pack` command is run with
the project root directory as the working directory. This allows the
build scripts to run correctly regardless of the working directory they
are invoked from.

PR Close #39455

scripts/build/package-builder.js

@@ -116,15 +116,17 @@ function buildTargetPackages(destPath, enableIvy, description) {
  *
  * @param {string} cmd The command to run.
  * @param {boolean} [captureStdout=false] Whether to return the output of the command.
+ * @param {import('child_process').ExecSyncOptions} [options] The options to pass to `execSync()`.
  * @return {string | undefined} The captured stdout output if `captureStdout: true` or `undefined`.
  */
-function exec(cmd, captureStdout) {
+function exec(cmd, captureStdout, options) {
   const output = execSync(cmd, {
     stdio: [
       /* stdin  */ 'inherit',
       /* stdout */ captureStdout ? 'pipe' : 'inherit',
       /* stderr */ 'inherit',
     ],
+    ...options,
   });
 
   if (captureStdout) {

scripts/build/zone-js-builder.js

@@ -48,7 +48,7 @@ function buildZoneJsPackage(destPath) {
 
   // Also create an archive so we can test the package itself.
   // Currently, the `npm_package.pack` rule does not work on Windows, so run `npm pack` directly.
-  exec(`npm pack ${buildOutputDir}`);
+  exec(`npm pack ${buildOutputDir}`, false, {cwd: baseDir});
 
   console.info(`# Copy npm_package artifacts to ${distTargetDir}`);
   rm('-rf', distTargetDir);