glsl2: Do algebraic optimizations after linking as well.

Linking brings in inlining of builtins, so we weren't catching the
(rcp(/sqrt(x)) -> rsq(x)) without it.

src/glsl/linker.cpp

@@ -1289,6 +1289,7 @@ link_shaders(struct gl_shader_program *prog)
 	 progress = do_tree_grafting(ir) || progress;
 	 progress = do_constant_variable_unlinked(ir) || progress;
 	 progress = do_constant_folding(ir) || progress;
+	 progress = do_algebraic(ir) || progress;
 	 progress = do_if_return(ir) || progress;
 #if 0
 	 if (ctx->Shader.EmitNoIfs)