Fix blendable FP32 texture caps on ES2 contexts
Fix blendable FP32 texture caps on ES2 contexts

Although the EXT_float_blend extension is defined only for ES 3.0+,
ANGLE exposes it on ES 2.0 client contexts.

Bug: angleproject:4595
Change-Id: I7451062ed8b1ab4eb18a8c7c1d37ee7383c8ea4b
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2172738
Commit-Queue: Geoff Lang <b6fc25fe0362055230985c05cbfa8adb741ccc0f@chromium.org>
Reviewed-by: Kenneth Russell <1ebccd90c2bc76de65b6f830f2128a91ed69fdfb@chromium.org>
Reviewed-by: Geoff Lang <b6fc25fe0362055230985c05cbfa8adb741ccc0f@chromium.org>

ppy/angle,ppy/angle,ppy/angle,ppy/angle