Make BitsetType enum uint32_t to avoid narrowing warnings

enum defaults to signed on win, and kTagged has 1<<31 causing
warning.

Full errors:

d:\src\cr3\src\v8\src\types.cc(1259): error C2220: warning treated as error - no 'object' file generated
d:\src\cr3\src\v8\src\types.cc(1241): note: while compiling class template member function 'void v8::internal::TypeImpl<v8::internal::ZoneTypeConfig>::BitsetType::Print(std::ostream &,v8::internal::TypeImpl<v8::internal::ZoneTypeConfig>::bitset)'
d:\src\cr3\src\v8\src\types.cc(1283): note: see reference to function template instantiation 'void v8::internal::TypeImpl<v8::internal::ZoneTypeConfig>::BitsetType::Print(std::ostream &,v8::internal::TypeImpl<v8::internal::ZoneTypeConfig>::bitset)' being compiled
d:\src\cr3\src\v8\src\types.cc(1355): note: see reference to class template instantiation 'v8::internal::TypeImpl<v8::internal::ZoneTypeConfig>::BitsetType' being compiled
d:\src\cr3\src\v8\src\types.cc(1259): warning C4838: conversion from 'int' to 'const v8::internal::TypeImpl<v8::internal::ZoneTypeConfig>::bitset' requires a narrowing conversion
d:\src\cr3\src\v8\src\types.cc(1259): note: to simplify migration, consider the temporary use of /Wv:18 flag with the version of the compiler with which you used to build without warnings
d:\src\cr3\src\v8\src\types.cc(323): warning C4838: conversion from '' to 'v8::internal::TypeImpl<v8::internal::ZoneTypeConfig>::bitset' requires a narrowing conversion
d:\src\cr3\src\v8\src\types.cc(323): note: to simplify migration, consider the temporary use of /Wv:18 flag with the version of the compiler with which you used to build without warnings
d:\src\cr3\src\v8\src\types.cc(315): note: while compiling class template static data member 'const v8::internal::TypeImpl<v8::internal::ZoneTypeConfig>::BitsetType::Boundary v8::internal::TypeImpl<v8::internal::ZoneTypeConfig>::BitsetType::BoundariesArray[]'
d:\src\cr3\src\v8\src\types.cc(1259): warning C4838: conversion from 'int' to 'const v8::internal::TypeImpl<v8::internal::HeapTypeConfig>::bitset' requires a narrowing conversion
d:\src\cr3\src\v8\src\types.cc(1259): note: to simplify migration, consider the temporary use of /Wv:18 flag with the version of the compiler with which you used to build without warnings
d:\src\cr3\src\v8\src\types.cc(1241): note: while compiling class template member function 'void v8::internal::TypeImpl<v8::internal::HeapTypeConfig>::BitsetType::Print(std::ostream &,v8::internal::TypeImpl<v8::internal::HeapTypeConfig>::bitset)'
d:\src\cr3\src\v8\src\types.cc(1283): note: see reference to function template instantiation 'void v8::internal::TypeImpl<v8::internal::HeapTypeConfig>::BitsetType::Print(std::ostream &,v8::internal::TypeImpl<v8::internal::HeapTypeConfig>::bitset)' being compiled
d:\src\cr3\src\v8\src\types.cc(1359): note: see reference to class template instantiation 'v8::internal::TypeImpl<v8::internal::HeapTypeConfig>::BitsetType' being compiled
d:\src\cr3\src\v8\src\types.cc(323): warning C4838: conversion from '' to 'v8::internal::TypeImpl<v8::internal::HeapTypeConfig>::bitset' requires a narrowing conversion
d:\src\cr3\src\v8\src\types.cc(323): note: to simplify migration, consider the temporary use of /Wv:18 flag with the version of the compiler with which you used to build without warnings
d:\src\cr3\src\v8\src\types.cc(315): note: while compiling class template static data member 'const v8::internal::TypeImpl<v8::internal::HeapTypeConfig>::BitsetType::Boundary v8::internal::TypeImpl<v8::internal::HeapTypeConfig>::BitsetType::BoundariesArray[]'

LOG=N
R=jochen@chromium.org
BUG=440500

Review URL: https://codereview.chromium.org/1055933004

Cr-Commit-Position: refs/heads/master@{#27854}

src/types.h

@@ -630,7 +630,7 @@ class TypeImpl<Config>::BitsetType : public TypeImpl<Config> {
  protected:
   friend class TypeImpl<Config>;
 
-  enum {
+  enum : uint32_t {
     #define DECLARE_TYPE(type, value) k##type = (value),
     BITSET_TYPE_LIST(DECLARE_TYPE)
     #undef DECLARE_TYPE