i965: Fix INTEL_DEBUG=shader_time for SIMD8 VS.

In commit 4ebeb71573, I deleted the
emit_shader_time_end() call in emit_urb_writes().  But I failed to add
it to run_vs(), as I intended.  So no data was recorded at all.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>

src/mesa/drivers/dri/i965/brw_fs.cpp

@@ -3877,6 +3877,9 @@ fs_visitor::run_vs()
 
    emit_urb_writes();
 
+   if (INTEL_DEBUG & DEBUG_SHADER_TIME)
+      emit_shader_time_end();
+
    calculate_cfg();
 
    optimize();