tickprocessor: apply c++filt manually on mac

`/bin/sh -c` trick wasn't working for several reasons:

* `/bin/sh -c "..."` expects the first argument after `"..."` to be a
  `$0`, not a `$1`. Previously `-n` wasn't passed to `nm` because of
  this, and many symbols were ordered improperly
* `c++filt` was applied not only to the names of the functions but to
  their `nm` prefixes like `t` and `a` (`t xxx` turns into
  `unsigned char xxx`).

Instead of applying `c++filt` wide and using `sh -c`, execute `nm` as
requested by `deps/v8/tools/tickprocessor.js` and apply `c++filt` to all
matching entries manually.

Included test demonstrates where previous approach failed: all builtins
were merged into `v8::internal::Builtins::~Builtins`, because they were
prefixed by `t` in `nm` output.

lib/internal/v8_prof_polyfill.js

@@ -38,11 +38,12 @@ const os = {
           /^[0-9a-f]+-[0-9a-f]+$/.test(arg)) {
         return '';
       }
-    } else if (process.platform === 'darwin') {
-      args.unshift('-c', name);
-      name = '/bin/sh';
     }
-    return cp.spawnSync(name, args).stdout.toString();
+    let out = cp.spawnSync(name, args).stdout.toString();
+    // Auto c++filt names, but not [iItT]
+    if (process.platform === 'darwin' && name === 'nm')
+      out = macCppfiltNm(out);
+    return out;
   }
 };
 const print = console.log;
@@ -100,3 +101,30 @@ function versionCheck() {
     }
   }
 }
+
+function macCppfiltNm(out) {
+  // Re-grouped copy-paste from `tickprocessor.js`
+  const FUNC_RE = /^([0-9a-fA-F]{8,16} [iItT] )(.*)$/gm;
+  let entries = out.match(FUNC_RE);
+  if (entries === null)
+    return out;
+
+  entries = entries.map((entry) => {
+    return entry.replace(/^[0-9a-fA-F]{8,16} [iItT] /, '')
+  });
+
+  let filtered;
+  try {
+    filtered = cp.spawnSync('c++filt', [ '-p' , '-i' ], {
+      input: entries.join('\n')
+    }).stdout.toString();
+  } catch (e) {
+    return out;
+  }
+
+  let i = 0;
+  filtered = filtered.split(/\n/g);
+  return out.replace(FUNC_RE, (all, prefix, postfix) => {
+    return prefix + (filtered[i++] || postfix);
+  });
+}

lib/internal/v8_prof_processor.js

@@ -20,8 +20,7 @@ scriptFiles.forEach(function(s) {
 
 var tickArguments = [];
 if (process.platform === 'darwin') {
-  const nm = 'foo() { nm "$@" | (c++filt -p -i || cat) }; foo $@';
-  tickArguments.push('--mac', '--nm=' + nm);
+  tickArguments.push('--mac');
 } else if (process.platform === 'win32') {
   tickArguments.push('--windows');
 }

test/parallel/test-tick-processor.js

@@ -43,6 +43,14 @@ runTest(/RunInDebugContext/,
          setTimeout(function() { process.exit(0); }, 2000);
          f();`);
 
+runTest(/Builtin_DateNow/,
+        `function f() {
+           this.ts = Date.now();
+           setImmediate(function() { new f(); });
+         };
+         setTimeout(function() { process.exit(0); }, 2000);
+         f();`);
+
 function runTest(pattern, code) {
   cp.execFileSync(process.execPath, ['-prof', '-pe', code]);
   var matches = fs.readdirSync(common.tmpDir);