LLVM JIT hangs/timeouts when returning large array of tuples

**Failure Details:**
`eval_ir_main` times out when executing the IR via LLVM JIT (`--use_llvm_jit`).

**Reproduction:**
```
/google/bin/releases/xls/eval_ir_main \
--testvector_textproto=testvector.pbtxt \
--use_llvm_jit \
sample.ir \
--logtostderr
```
(Using files extracted from `crasher_2026-05-23_85e7.x`)

**Root Cause:**
The top function has a complex return type containing a large array of tuples:
`-> (bits[1], (bits[1], bits[1], bits[1], bits[1])[1818])`

Even when the IR is minimized to simply return a literal of this type:
```
top fn __sample__main(...) -> (bits[1], (bits[1], bits[1], bits[1], bits[1])[1818]) {
ret literal.14276: ... = literal(...)
}
```
LLVM JIT (`eval_ir_main`) still hangs/timeouts even with a single input vector.
This suggests the issue is in how LLVM or the XLS LLVM JIT bridge handles extremely large or complex return types or literal values.

**Minimizer Notes:**
`ir_minimizer_main` crashed with OOM (tcmalloc) when attempting to minimize `sample.ir`, though it produced a partially minimized file (`minimized.ir`) which completely folded the logic into the literal return shown above.