This reverts commit a4b506f7.

Reason for revert: WebGL crash
https://bugs.chromium.org/p/angleproject/issues/detail?id=4616

Original change's description:
> No-Op draws when no active VS and/or FS is present
> 
> According to the OpenGL ES 3.1 spec:
> 
> 7.3. PROGRAM OBJECTS
> If there is no active program for the vertex or fragment shader
> stages, the results of vertex and fragment shader execution will
> respectively be undefined. However, this is not an error.
> 
> To handle this, if no VS or FS is present in the active Program/PPO,
> we will no-op the draw command.
> 
> Bug: angleproject:3570
> Test: KHR-GLES31.core.sepshaderobjs.StateInteraction
> Change-Id: If19e9fbb1bc09fa0d490832079bb9f514eab6035
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2136386
> Reviewed-by: Jamie Madill <jmadill@chromium.org>
> Commit-Queue: Tim Van Patten <timvp@google.com>

TBR=timvp@google.com,jmadill@chromium.org,cclao@google.com

Change-Id: Ia24c4156ff7779b69c1f3f705f1a91cbb1c9684c
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: angleproject:3570
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2184849Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com>
Commit-Queue: Courtney Goeltzenleuchter <courtneygo@google.com>