This fixes a corner case with the matching for a {UBFX} instruction.
According to the ISA reference "UBFX Rd, Rn, #lsb, #width" is only valid
for "#width" in the [1;32-#lsb] range. Specifically a "#width" of 0 is
invalid but was not checked against by the instruction selector.

R=ahaas@chromium.org
TEST=mjsunit/regress/wasm/regress-924905
BUG=chromium:924905

Change-Id: I470671282b215be62dfd147a619a0d317f7cc746
Reviewed-on: https://chromium-review.googlesource.com/c/1435939Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59096}