mesa: return initial value for VALIDATE_STATUS if pipe not bound

From OpenGL 4.5 Core spec (7.13):

    "If pipeline is a name that has been generated (without subsequent
    deletion) by GenProgramPipelines, but refers to a program pipeline
    object that has not been previously bound, the GL first creates a
    new state vector in the same manner as when BindProgramPipeline
    creates a new program pipeline object."

I interpret this as "If GetProgramPipelineiv gets called without a
bound (but valid) pipeline object, the state should reflect initial
state of a new pipeline object." This is also expected behaviour by
ES31-CTS.sepshaderobjs.PipelineApi conformance test.

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Marta Lofstedt <marta.lofstedt@intel.com>

src/mesa/main/pipelineobj.c

@@ -614,7 +614,8 @@ _mesa_GetProgramPipelineiv(GLuint pipeline, GLenum pname, GLint *params)
       *params = pipe->InfoLog ? strlen(pipe->InfoLog) + 1 : 0;
       return;
    case GL_VALIDATE_STATUS:
-      *params = pipe->Validated;
+      /* If pipeline is not bound, return initial value 0. */
+      *params = (ctx->_Shader->Name != pipe->Name) ? 0 : pipe->Validated;
       return;
    case GL_VERTEX_SHADER:
       *params = pipe->CurrentProgram[MESA_SHADER_VERTEX]