Change git repository initialization method. Instead of passing git
command to system(), internal git command functions are used to avoid
external git error.
Fix bugs in fuzzers. Aim to solve double freeing of pointers and divided
by zero float pointer exception and size calculation.
Fixed os-fuzz issue 51681 and 51688.
This PR aims to create fuzzers for the git project that fuzz each of the
git commands. The initial fuzzers created are targetting the following
git commands.
1. git-version
2. git-status
3. git-diff
4. git-diff-tree
5. git-diff-files
6. git-diff-index
Arthur Chan