Clang crash on global-scope statement with ellipsis ('...')

- crash on invalid input
- bug found from fuzzing

## Minimized Code
```c
g(h(x)...)
```
## Full Example Code
```c
int g(int);
int h(int);
int x = 0;
g(h(x)...); // crash
```
Note:
- Crash only found in clang, not present in clang++
- If the same statement is moved inside a function (ex. main()), or assigned to a variable, the crash does not occur.

## CompilerExplorer
https://godbolt.org/z/j7q9Pcfh1

Start by reproducing the crash with the minimized code and the full example in Clang, using the linked CompilerExplorer case if helpful. Compare the same inputs in clang++ and with the statement moved inside a function or assigned to a variable; done means the global-scope ellipsis input no longer crashes and the relevant regression coverage passes.

Written by the indexing model from the issue text.