cmd/compile: non-retpoline-compatible errors [1.19 backport]

[gopherbot]

@randall77 requested issue #57097 to be considered for backport to the next 1.19 minor release.

@gopherbot please open a backport issue to 1.19.

This issue makes large switches fail to compile in -spectre=all or -spectre=ret mode.

[gopherbot]

Change https://go.dev/cl/455416 mentions this issue: [release-branch.go1.19] cmd/compile: turn off jump tables when spectre retpolines are on

[gopherbot]

Closed by merging 1565780 to release-branch.go1.19.