[clang] [C] Add -Wjump-bypasses-init (PR #138009)

[Arthur Eubanks via cfe-commits]

aeubanks wrote:

this causes a `-Wmicrosoft-goto` warning on
```
$ cat /tmp/a.c
void f() {
        goto l;
        int i = 0;
l:
}
$ bin/clang-cl /c /tmp/a.c
...
/tmp/a.c(2,2): warning: jump from this goto statement to its label is a Microsoft extension [-Wmicrosoft-goto]
    2 |         goto l;
      |         ^
/tmp/a.c(3,6): note: jump bypasses variable initialization
    3 |         int i = 0;
      |             ^
```
where there was none previously. is this intended?

https://github.com/llvm/llvm-project/pull/138009