Trusty: Move tipc fuzzer connection to end of iteration

We detect a TA crash by not being able to reconnect to its channel. We
were previously connecting to the TA at the beginning of each fuzz
iteration, but this results in only detecting a crash on the following
iteration. By moving this connection to the end of the fuzz iteration,
we can detect a crash corresponding to the correct fuzz iteration and
libFuzzer will produce the correct crashing input.

Test: /data/fuzz/arm64/trusty_keymaster_fuzzer/trusty_keymaster_fuzzer
Bug: 185407818
Change-Id: I6808c72611fcabab5b314218f8b588dd7d944188