[shaders] Fix off-by-one in error reporting.
[shaders] Fix off-by-one in error reporting.

Change-Id: I9dee9d070b0db33b25cf2f043cb35ed0e14c570f
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/461060
Reviewed-by: Brian Osman <794c0b5534edf5601d88e1d41975d0262da12894@google.com>
Commit-Queue: Joe Gregorio <b9cf2471ff6d33504cafe8e6f356b732b2cadced@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot