sampler2DRect was placed under ESSL while sampler2DArrayShadow was
placed under desktop GLSL.  They are swapped.

Bug: angleproject:3569
Change-Id: Ibf39868d4cd702d9d1da7fc286171bb70b80d6df
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1975430Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>