tools: fix tickprocessor Cpp symbols on mac

Despite man page documentation:

    -f Display the symbol table of a dynamic library flat (as one
       file not separate modules).

`nm` on mac treats `-f` as a shorthand for `-format`. The `-f` argument
does not seem to be required, so just remove it completely.

(For `-format` documentation - see `nm --help` on mac).

BUG=

Review URL: https://codereview.chromium.org/1840633002

Cr-Commit-Position: refs/heads/master@{#35445}

tools/tickprocessor.js

@@ -670,8 +670,11 @@ inherits(MacCppEntriesProvider, UnixCppEntriesProvider);
 MacCppEntriesProvider.prototype.loadSymbols = function(libName) {
   this.parsePos = 0;
   libName = this.targetRootFS + libName;
+
+  // It seems that in OS X `nm` thinks that `-f` is a format option, not a
+  // "flat" display option flag.
   try {
-    this.symbols = [os.system(this.nmExec, ['-n', '-f', libName], -1, -1), ''];
+    this.symbols = [os.system(this.nmExec, ['-n', libName], -1, -1), ''];
   } catch (e) {
     // If the library cannot be found on this system let's not panic.
     this.symbols = '';