glsl-es-1.00: Only unroll a do-while-false loop once
This was the smallest test case that I could make that would reproduce the bug, generate actual instructions (instead of constant folding to nothing), and be small enough to run on any GPU supported by Mesa that has GLES 2.0 (i.e., i915).
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110953