Support for 64-bit Platform

* All: [BUG FIX] Corrected the tests that are failed by the pointer sizes and alignments are changed.
* All: [BUG FIX] Corrected the tests that are failed by the difference of metadata token between 32-bit and 64-bit.
* All: [BUG FIX] Corrected 'warning C4244'.
* Hosting: Improve the precision to determine whether the PE Header is 32-bit or 64-bit.
* Metadata: [BUG FIX] Corrected the wrong determination for ProcessorArchitecture of an Assembly.