mesa: Don't null deref looking for Mesa IR code at compile time.

The new compiler doesn't generate Mesa IR at compile time, and that
compile time code previously wouldn't have reflected the link time
code that actually got used.  But do dump the info log of the compile
regardless.

src/mesa/program/prog_print.c

@@ -1031,11 +1031,9 @@ _mesa_write_shader_to_file(const struct gl_shader *shader)
 
    fprintf(f, "/* Compile status: %s */\n",
            shader->CompileStatus ? "ok" : "fail");
-   if (!shader->CompileStatus) {
-      fprintf(f, "/* Log Info: */\n");
-      fputs(shader->InfoLog, f);
-   }
-   else {
+   fprintf(f, "/* Log Info: */\n");
+   fputs(shader->InfoLog, f);
+   if (shader->CompileStatus && shader->Program) {
       fprintf(f, "/* GPU code */\n");
       fprintf(f, "/*\n");
       _mesa_fprint_program_opt(f, shader->Program, PROG_PRINT_DEBUG, GL_TRUE);