Turn Flags into a uint32_t typedef.

We cannot rely on C++ compilers inferring the int-type from the enum
value range. Whereas Linux/OSX find uint32_t as type for [0,MaxUInt32],
Windows insists it's int.

Update the test to execute its original intent on all platforms: 1 value
larger than max arguments, 1 smaller than max arguments (on all
platforms). This makes the test run a lot faster.

BUG=chromium:194749

Review URL: https://chromiumcodereview.appspot.com/12507010

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13988 ce2b1a6d-e550-0410-aec6-3dcde31c8c00