fuzz: select fuzz target using executable name

fuzz: select fuzz target using executable name

The fuzzers are built into a binary (e.g. qemu-fuzz-i386). To select the
device to fuzz/fuzz target, we usually use the --fuzz-target= argument.
This commit allows the fuzz-target to be specified using the name of the
executable. If the executable name ends with -target-FUZZ_TARGET, then
we select the fuzz target based on this name, rather than the
--fuzz-target argument. This is useful for systems such as oss-fuzz
where we don't have control of the arguments passed to the fuzzer.

[Fixed incorrect indentation.
--Stefan]

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-id: 20200421182230.6313-1-alxndr@bu.edu
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>