x/tools/gopls/test: TestCommandLine/GOPATH/Renames/b_Goodbye failure with `apply unified gave wrong result`

[bcmills]

            --- FAIL: TestCommandLine/GOPATH/Renames/b_Goodbye (0.28s)
                rename.go:24: rename failed with /ramdisk8GB/workdir-host-aix-ppc64-osuosl/tmp/TestCommandLine_GOPATH3623923662/lsp/src/golang.org/x/tools/internal/lsp/rename/b/b.go:20:6-11 Goodbye
…
                format.go:84: apply unified gave wrong result for /ramdisk8GB/workdir-host-aix-ppc64-osuosl/tmp/TestCommandLine_GOPATH3623923662/lsp/src/golang.org/x/tools/internal/lsp/rename/b/b.go expected:
                    b.go:
                    package b

greplogs -l -e 'apply unified gave wrong result' --since=2022-02-01
2022-08-11T14:11:53-3807419-2340d37/aix-ppc64

[findleyr]

CC @pjweinb @adonovan : is this a dupe of our previous bug in ApplyUnified, which I think is fixed?