This change updates the expected output of the gdb debugging session
in the TestNexting internal/ssa test, aligning it with the changes
introduced in CL 134555.

Fixes #27863

Change-Id: I29e747930c7668b429e8936ad230c4d6aa24fdac
Reviewed-on: https://go-review.googlesource.com/137455Reviewed-by: Than McIntosh <thanm@google.com>