cmd/compile: bug in cmd/compile/internal/escape.(*escape).newLoc

Issue created by [stacks](https://pkg.go.dev/golang.org/x/tools/gopls/internal/telemetry/cmd/stacks).

This stack `qzye-A` was [reported by telemetry](https://storage.googleapis.com/prod-telemetry-merged/2024-11-29.json):

- `compile/bug`
- [`cmd/compile/internal/base.FatalfAt:+3`](https://cs.opensource.google/go/go/+/go1.23.2:src/cmd/compile/internal/base/print.go;l=215)
- [`cmd/compile/internal/escape.(*escape).newLoc:+28`](https://cs.opensource.google/go/go/+/go1.23.2:src/cmd/compile/internal/escape/graph.go;l=294)
- `cmd/compile/internal/escape.(*batch).initFunc:=186`
- [`cmd/compile/internal/escape.Batch:+12`](https://cs.opensource.google/go/go/+/go1.23.2:src/cmd/compile/internal/escape/escape.go;l=139)
- [`cmd/compile/internal/ir.(*bottomUpVisitor).visit:+58`](https://cs.opensource.google/go/go/+/go1.23.2:src/cmd/compile/internal/ir/scc.go;l=121)
- [`cmd/compile/internal/ir.(*bottomUpVisitor).visit.func1:+2`](https://cs.opensource.google/go/go/+/go1.23.2:src/cmd/compile/internal/ir/scc.go;l=78)
- [`cmd/compile/internal/ir.(*bottomUpVisitor).visit.func2:+12`](https://cs.opensource.google/go/go/+/go1.23.2:src/cmd/compile/internal/ir/scc.go;l=96)
- [`cmd/compile/internal/ir.Visit.func1:+1`](https://cs.opensource.google/go/go/+/go1.23.2:src/cmd/compile/internal/ir/visit.go;l=105)
- [`cmd/compile/internal/ir.(*ConvExpr).doChildren:+4`](https://cs.opensource.google/go/go/+/go1.23.2:src/cmd/compile/internal/ir/node_gen.go;l=484)
- [`cmd/compile/internal/ir.DoChildren:=94`](https://cs.opensource.google/go/go/+/go1.23.2:src/cmd/compile/internal/ir/visit.go;l=94)
- [`cmd/compile/internal/ir.Visit.func1:+2`](https://cs.opensource.google/go/go/+/go1.23.2:src/cmd/compile/internal/ir/visit.go;l=106)
- `cmd/compile/internal/ir.doNodes:=1797`
- [`cmd/compile/internal/ir.(*CompLitExpr).doChildren:+4`](https://cs.opensource.google/go/go/+/go1.23.2:src/cmd/compile/internal/ir/node_gen.go;l=448)
- [`cmd/compile/internal/ir.DoChildren:=94`](https://cs.opensource.google/go/go/+/go1.23.2:src/cmd/compile/internal/ir/visit.go;l=94)
- [`cmd/compile/internal/ir.Visit.func1:+2`](https://cs.opensource.google/go/go/+/go1.23.2:src/cmd/compile/internal/ir/visit.go;l=106)
- `cmd/compile/internal/ir.doNodes:=1797`
```
cmd/compile@go1.23.2 go1.23.2 linux/amd64 (1)
```

Start at cmd/compile/internal/escape/graph.go's newLoc, then follow batch.initFunc and escape.Batch in the reported stack. Use the telemetry stack and Go 1.23.2 source locations to find a reproducible compiler input; done means the crash is explained and fixed with coverage for that input.

Written by the indexing model from the issue text.