Instructions to work on the test suite.

Format of ia32_test_insn.S is:
    GNU as assembler input... [# expected libdisasm output [# notes/XFAIL]]

Run XFAIL tests, with diff output:
    ./run-test.sh --try-xfail --diff

Examine byte code generating a specific instruction:
    ./asmdisasm.pl *.S blah.o | grep ^INSTRUCTION
