Disabling nacl_win64 targets when building in target_arch!=ia32 mode.

When building on windows with target_arch=x64, we no longer need win32 targets
forced to be 64-bit. This gates out these targets when target_arch!=ia32.
(Prior CL dropped the minimal set to break the dependency between these targets
and the rest of the build. This eliminates them completely.)

BUG=None
TEST=None
R=jschuh@chromium.org,thestig@chromium.org
TBR=darin@chromium.org,abodenha@chromium.org,apatrick@chromium.org,sra@chromium.org,wtc@chromium.org

Review URL: https://chromiumcodereview.appspot.com/11929039

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@177959 0039d316-1c4b-4281-b951-d872f2087c98

• base/allocator/allocator.gyp[diff]
• base/base.gyp[diff]
• base/third_party/dynamic_annotations/dynamic_annotations.gyp[diff]
• breakpad/breakpad_handler.gypi[diff]
• breakpad/breakpad_sender.gypi[diff]
• chrome/app/policy/cloud_policy_codegen.gyp[diff]
• chrome/chrome.gyp[diff]
• chrome/chrome_installer.gypi[diff]
• chrome/chrome_installer_util.gypi[diff]
• chrome/chrome_tests.gypi[diff]
• chrome/common_constants.gyp[diff]
• cloud_print/cloud_print.gyp[diff]
• courgette/courgette.gyp[diff]
• crypto/crypto.gyp[diff]
• gpu/gpu.gyp[diff]
• ipc/ipc.gyp[diff]
• ppapi/ppapi_internal.gyp[diff]
• sandbox/win/sandbox_win.gypi[diff]