i965/meta: Store stencil texturing mode

i965/meta: Store stencil texturing mode

Meta path needs to keep the current texture object's state. Fixes
the following gles3 cts tests on bdw:

framebuffer_blit_functionality_negative_width_blit.test: fail
framebuffer_blit_functionality_all_buffer_blit.test: fail
framebuffer_blit_functionality_negative_height_blit.test: fail
framebuffer_blit_functionality_missing_buffers_blit.test: fail
framebuffer_blit_functionality_negative_dimensions_blit.test: fail
framebuffer_blit_functionality_minifying_blit.test: fail
framebuffer_blit_functionality_magnifying_blit.test: fail

Signed-off-by: Topi Pohjolainen <topi.pohjolainen@intel.com>
Cc: "10.2" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>