.zshrc not sourced / zsh not used even if default? Causes rustc to not show up

- VS Code Version: 1.36.1
- OS Version: centOS 7
- Code Runner Version: 0.9.12

**Describe the bug**
When trying to run a rust progarm with the default configuration (`rustc $fileName`) I get
```
/bin/sh: rustc: command not found
```

If I run rustc normally from my terminal, I am able to compile my program.

I am using zsh, and I noticed that if I use a custom command for rust in the settings and I explicitly source my .zshrc file:
```
"code-runner.executorMap": {
"rust": "cd $dir && source ~/.zshrc && rustc $fileName && $dir$fileNameWithoutExt"
}
```
then the command runs fine.

If I echo my $SHELL in the code runner command for rust, I get /bin/zsh. But the error I get from running the default command says `/bin/sh: rustc: command not found`. Does this mean that code runner is somehow not using my default terminal (zsh)? Or for some reasons it is not sourcing my .zshrc? If I print my PATH in the code runner command, I noticed that I get the PATH defined by my .bashrc, and not my .zhsrc file.

Empieza reproduciendo el comando Rust predeterminado en CentOS 7 con zsh y, a continuación, compara el shell y PATH con el comando personalizado que ejecuta source ~/.zshrc. Se considera terminado cuando el executor rustc predeterminado puede encontrar rustc sin requerir que los usuarios añadan un comando de executor personalizado.

Escrito por el modelo de indexación a partir del texto del issue.