custom_border_colors_without_format was disabled on android for anv to
add support for VK_FORMAT_A4R4G4B4_UNORM_PACK16_EXT.
See https://gitlab.freedesktop.org/mesa/mesa/-/issues/12511#note_2749432
ANGLE's vulkan backend needs custom_border_colors_without_format for
EXT_texture_border_clamp which is required for
GL_ANDROID_extension_pack_es31a so enable it when run under ANGLE which
doesn't utilize VK_FORMAT_A4R4G4B4_UNORM_PACK16_EXT.
Signed-off-by: Juston Li <justonli@google.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34490>
762b749f9f