This adds support for get_local and set_local to the wasm compile
fuzzer. Each function will have between 0 and 32 locals of random type.
For set_local, we generate a value of the respective type and store it
in the local. For get_local, we load any local and convert it to the
wanted type.
Note that with get_local, we now also check that parameters are passed
correctly between functions.

Drive-by: Fix parameters passed to the main function (was [1,2,3] for
the interpreter, but [1,1,1] for compiled code).

R=ahaas@chromium.org, eholk@chromium.org

Change-Id: I38e85fe25b1fb4ac298fa81ec8e33711294e78bb
Reviewed-on: https://chromium-review.googlesource.com/847535Reviewed-by: Eric Holk <eholk@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50355}