cmd/compile: function argument hiding built-in function results in a compiler crash [1.11 backport]

[gopherbot]

@FiloSottile requested issue #27356 to be considered for backport to the next 1.11 minor release.

@gopherbot please file this to be considered for backport to 1.11. This is a regression.

[gopherbot]

Change https://golang.org/cl/139103 mentions this issue: [release-branch.go1.11] cmd/compile: don't crash reporting misuse of shadowed built-in function

[gopherbot]

Closed by merging 19fe28a to release-branch.go1.11.