SwiftShader's OpenGL ES support is deprecated in favor of the Vulkan
implementation, with ANGLE providing backward compatibility for GLES use
cases. There are no known uses of our OpenGL ES 1.1 implementation left,
so this change removes its code entirely.

Bug: b/147516027
Change-Id: I72bcd7a648df435bd5c00caf3b4bb35965a0c116
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/53909
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>