Stub out pnacl-opt and pnacl-finalize tools for scons built_elsewhere=1

Stub out pnacl-opt and pnacl-finalize tools for scons built_elsewhere=1

This is required to make the PSO generation test pass on ARM hardware;
(or more specifically, opt will run on the x86 bot, and get stubbed
out on the hardware bot). Stubbing out pnacl-finalize isn't
required for that particular test but is just for completeness.
R=mseaborn@chromium.org
BUG= https://code.google.com/p/nativeclient/issues/detail?id=3873

Committed: https://src.chromium.org/viewvc/native_client?view=rev&revision=13469

[Mark Seaborn, 2014-07-10 20:27:59]

LGTM

This is required to roll the PNaCl toolchain rev, right?  Before the roll, the
test is disabled on the main bots by the check for TOOLCHAIN_FEATURE_VERSION.

[Derek Schuff, 2014-07-10 20:28:17]

On 2014/07/10 20:27:59, Mark Seaborn wrote:
> LGTM
> 
> This is required to roll the PNaCl toolchain rev, right?  Before the roll, the
> test is disabled on the main bots by the check for TOOLCHAIN_FEATURE_VERSION.

Yes, exactly.

[Derek Schuff, 2014-07-10 20:42:35]

Committed patchset #1 manually as r13469 (presubmit successful).