[cgen-ibld-dis] fill_cache vs variable sized opcodes
M32C opcodes range from one to ten bytes long, so occasionally
fill_cache would attempt to read a "word" that extended beyond the end
of the memory segment, and would fail (this shows up with "objdump
There was already a partial test for this, but it didn't account for
opcodes longer than a word. This patch changes the logic to account
for both short opcodes and long-but-not-whole-words opcodes, although
it uses "min_insn_bitsize < base_insn_bitsize" as a generic test for
"variable length opcodes".
* cgen-ibld.in (extract_normal): Avoid memory range errors.