These extensions are superseded by EXT_color_buffer_float and not needed to support
WebGL2.  Allowing them to expose rendering to RGB[A]32F when EXT_color_buffer_float
is not supported causes dEQP failures.

BUG=angleproject:3939

Change-Id: Ib50a061526f29fc0628e732123c04a22800345dc
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1832525Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Alexis Hétu <sugoi@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>