gui: explicitly crash in Surface's ctor if bufferProducer is null

it will crash anyway, but this way crash is
easier to debug.

Bug: 412426167
Test: presubmit
Flag: EXEMPT no behavior change
Change-Id: I1132a7e669a9c536818f2fbd31e3d0bfff7a408a
Signed-off-by: Roman Kiryanov <rkir@google.com>