llvmpipe/ci: drop fraction for asan tests that takes 1.5 min without fraction

The fraction was making it run for only 10-12 seconds, which is wasteful
considering the huge overhead.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33581>

src/gallium/drivers/llvmpipe/ci/deqp-llvmpipe-asan.toml

@@ -7,7 +7,6 @@ deqp_args = [
     "--deqp-surface-width=256", "--deqp-surface-height=256",
     "--deqp-surface-type=pbuffer", "--deqp-gl-config-name=rgba8888d24s8ms0", "--deqp-visibility=hidden"
 ]
-fraction = 10
 version_check = "GL ES 3.2.*git"
 renderer_check = "llvmpipe"
   [deqp.env]