This test is ported from webgl conformance test
WebglConformance_conformance2_glsl3_short_circuiting_in_loop_condition.
Since HLSL and ESSL have different rules to process short-circuit evaluation,
this patch will use the final flattened shader so that the translated HLSL
is almost same with the current ES shader.

BUG=843369
TEST=angle_end2end_tests

Change-Id: Ibc742f8ac4592a83c4c7dad37a64a5563eb58bd5
Reviewed-on: https://chromium-review.googlesource.com/1090328
Commit-Queue: Jiajia Qin <jiajia.qin@intel.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>