[analyzer] Explicit Return and __attribute__((cleanup(..)))

Uncommenting the explicit return in `process_data` will trigger the following:

```Bash
peng@hackerlife2:~/Desktop$ /home/peng/Downloads/LLVM-21.1.2-Linux-X64/bin/scan-build /home/peng/Downloads/LLVM-21.1.2-Linux-X64/bin/clang test.c
scan-build: Using '/home/peng/Downloads/LLVM-21.1.2-Linux-X64/bin/clang-21' for static analysis
test.c:30:5: warning: Potential leak of memory pointed to by 'data' [unix.Malloc]
30 | return;
| ^~~~~~
1 warning generated.
scan-build: Analysis run complete.
scan-build: 1 bug found.
scan-build: Run 'scan-view /tmp/scan-build-2025-09-24-215520-185566-1' to examine bug reports.

```

```C
#include
#include
#include

// This could be unix.Malloc or any other allocation function
void* my_malloc(size_t size) {
return malloc(size);
}

// The cleanup function.
// IMPORTANT: It takes a pointer to the variable, so char** for a char* variable.
void free_pointer(char **p) {
printf("Cleanup function called for address: %p\n", (void*)*p);
free(*p); // Dereference to get the actual pointer and free it.
}

void process_data() {
// The magic happens here. The variable 'data' is tied to the 'free_pointer' function.
__attribute__((cleanup(free_pointer))) char *data = my_malloc(100);

if (!data) {
perror("Allocation failed");
return;
}

strcpy(data, "Hello, Clang Static Analyzer!");
printf("Data processed: %s\n", data);

// Uncommenting the next line will trigger LEAK WARNING
// return;

// No need to call free(data) here.
// The cleanup function is called automatically when process_data() returns.
}

int main() {
process_data();
printf("Back in main. Memory should be freed.\n");
return 0;
}
```

Reproduce the warning with the provided test.c program using scan-build and clang, comparing the commented and uncommented return paths. Trace how the analyzer handles __attribute__((cleanup(free_pointer))) during an explicit return; done means the valid cleanup path is not reported as a leak while genuine leaks remain diagnosable.

Written by the indexing model from the issue text.