GL_HALF_FLOAT and GL_HALF_FLOAT_OES have different
values and only the latter is valid in GLES 2.0.
However, angle_deqp_khr_gles2_tests expects these
two enums to be treated as interchangable. This
is a bug in deqp, so the affected tests should
be expected to fail until the bug is fixed.

Bug: angleproject:3451
Test: dEQP.KHR_GLES2/core_internalformat_texture2d_*_half_float_*
Change-Id: If3a8078e592b18c60c883dfebd246435761a4423
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1743051
Commit-Queue: Mohan Maiya <m.maiya@samsung.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>