Updated the way we build AFL++ fuzz binaries

Test: Built AFL fuzzers individually and built all using haiku command
and built libfuzzers individually and also by using haiku command. Ran
selected fuzzers manually to ensure fuzzing still worked.

Description: Previously we needed to add cc_afl_fuzz to build an afl fuzz binary,
however, to turn current libFuzzers into AFL fuzzers this would required
an update to each Android.bp file which is a lot of work, and would also
require an approval from each Android.bp file owner, which is even more
work.

To get around this (and also to match how AFL fuzzers are built in G3)
we will build AFL++ fuzz binaries by command line option FUZZ_FRAMEWORK.
When FUZZ_FRAMEWORK=AFL is set, all cc_fuzz modules will be built

Change-Id: I994bde63b759046c9e3d75d3acfdc1352412005b