Fix mismatched C free of memory allocated with C++ new

[dylanahsmith]

Problem

There were a couple of places where C++ new was used in v8go.cc, then C.free was used on that pointer in Go.

Mixing these is technically undefined behaviour, even though new and delete is often implemented as a wrapper around malloc and free

Solution

I used malloc to allocate these values so they can be safely freed using C.free.

Looks like clang-format was missed on the existing code in master, so using that produced some more noise to this change, but I isolated that to the second commit in this PR

[codecov]

Codecov Report

Merging #220 (2a5759c) into master (ea7debf) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #220   +/-   ##
=======================================
  Coverage   95.59%   95.59%           
=======================================
  Files          16       16           
  Lines         545      545           
=======================================
  Hits          521      521           
  Misses         15       15           
  Partials        9        9           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ea7debf...2a5759c. Read the comment docs.