Use the PQ OETF and EOTF to ensure that intermediate fragment shader operations
using PQ are in linear BT.2020 rather than PQ and HLG-1 BT.2020.
Also, swap the OETF and EOTF in shaders, as they were used incorrectly before
Manually tested by verifying transformer demo HLG and PQ videos look the same with and without this CL, including with a BitmapOverlayProcessor enabled to test flows both with one MatrixTransformationProcessor that skips HDR TFs, and with one that doesn't.
PiperOrigin-RevId: 469736067
(cherry picked from commit a2139109e3e67d830be8fd5a342687a569009270)
c827c80b22