Add support for 32-bit and 64-bit Windows compiles in GN.

Rename ia32 and ia64 to x86 and x64

BUG=297677, 322109
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Review URL: https://codereview.chromium.org/83733005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236851 0039d316-1c4b-4281-b951-d872f2087c98
6 files changed