Expose EXT_float_blend

Expose EXT_float_blend in Swiftshader without actually doing validation.

Also fix some missing instructions in dEQP.md.

dEQP test results: there are quite a lot failures from my locally run tests.
Not sure if they used to be there, or is introduced by my change.

16/16 of the blend tests passed.


Bug: chromium:968830
Change-Id: Ifa2bb09788899b004d62388311aa7d2aa6ad6df3
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/32888
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Sean Risser <srisser@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Tested-by: Shrek Shao <shrekshao@google.com>

docs/dEQP.md

diff --git a/docs/dEQP.md b/docs/dEQP.md
index b3f9c11..8465301 100644
--- a/docs/dEQP.md
+++ b/docs/dEQP.md
@@ -229,6 +229,7 @@
 * Search for `../candy-build/deqp-wgl/execserver/Release` and replace that by `<path to deqp>/build/execserver/`

 * Just above, add an option to CommandLine: `--deqp-gl-context-type=egl`

 * Just below, remove 'Debug/' from the BinaryPath.

+* Just one more line below, replace `../candy-build/deqp-wgl/` with `<path to deqp>/build`.

 

 Testing OpenGL ES

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