Don't use gl::Error in validation.

Instead pass error code and error message directly to the Context. As
a side effect every validation error has an associated message now.

Reduces binary size by almost 100k.

Bug: angleproject:2957
Change-Id: I045e8ab57f8f9d787654a32f6f037011fe3a9f24
Reviewed-on: https://chromium-review.googlesource.com/c/1335890
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>

Author: null77

src/libANGLE/Error.h

@@ -98,14 +98,6 @@ using ErrorStream = angle::ErrorStreamBase<Error, GLenum, GL_NO_ERROR, GLenum, E
 
 }  // namespace priv
 
-using InvalidEnum                 = priv::ErrorStream<GL_INVALID_ENUM>;
-using InvalidValue                = priv::ErrorStream<GL_INVALID_VALUE>;
-using InvalidOperation            = priv::ErrorStream<GL_INVALID_OPERATION>;
-using StackOverflow               = priv::ErrorStream<GL_STACK_OVERFLOW>;
-using StackUnderflow              = priv::ErrorStream<GL_STACK_UNDERFLOW>;
-using OutOfMemory                 = priv::ErrorStream<GL_OUT_OF_MEMORY>;
-using InvalidFramebufferOperation = priv::ErrorStream<GL_INVALID_FRAMEBUFFER_OPERATION>;
-
 inline Error NoError()
 {
     return Error::NoError();