Rewrite cpp-define-generator

The new method works by generating temporary per-architecture
human-readable object file with the constants embedded in it.
Python script extracts those values and generates the header.

This means the values can now implicitly depend on pointer size,
compile time flags, or ABI specific object layout with no hacks.

Test: test-art-host-gtest-arch_test
Change-Id: Id6e8c77c01f9d6c49cd6d40e3487b56fa4777349