Port 53d4dfc3

Original Commit Message:

    Compress the parameter count (and function length) stored in
    SharedFunctionInfo to a uint16_t. This limits us to 2^16 - 1 parameters
    per function, minus one for the "don't adapt arguments" sentinel value,
    which is one fewer than Code::kMaxArguments was already. Anyway, 65534
    arguments should be enough for anyone!

    This drops SFI size by 4 bytes.

R=leszeks@chromium.org, joransiu@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: I23db04fd41ad577949cd8d45bab82c77019d9350
Reviewed-on: https://chromium-review.googlesource.com/1081450Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#53464}