Remove simple_fuzzer dir.

simple_fuzzers are a tiny subset of func_fuzzers
and are unnecessary now.
Test: mmma test/vts-testcase/fuzz
Change-Id: I572a2419489f6874eaf63cd32e6b8ad8e3a10e56

(cherry picked from commit f23e4aa10a2ef0e1e8687462c2c0c74308cae0dc)
(cherry picked from commit 02719f6c3cfa534513625caa45da5ec48239376e)
24 files changed