[lldb] Oversized DW_OP_piece triggers an unbounded allocation and aborts LLDB

A malformed DWARF expression can terminate LLDB by supplying an oversized byte-size operand to `DW_OP_piece`. LLDB does not validate the operand before using it to resize the piece buffer, so `DW_OP_piece 0x2000000000000000` can trigger a `2^61`-byte (2 EiB) allocation attempt and reach LLVM's fatal out-of-memory handler.

Malformed debug information should produce a normal expression-evaluation error, not abort the debugger process.

## Minimal Case

```text
DW_OP_lit0
DW_OP_piece 0x2000000000000000
```

Instead of rejecting the oversized piece, LLDB terminates with:

```text
LLVM ERROR: out of memory
Allocation failed
```

Start in LLDB's DW_OP_piece expression-evaluation path and reproduce the minimal DWARF expression shown in the issue. Done means the oversized operand is rejected with a normal expression-evaluation error rather than triggering an unbounded allocation or abort; the payload names no source file or test.

Written by the indexing model from the issue text.