cmd/cgo/internal/testsanitizers: skip asan tests when FIPS140 mode is on

cmd/cgo/internal/testsanitizers: skip asan tests when FIPS140 mode is on

Executing "GODEBUG=fips140=on go test -run TestASAN
./cmd/cgo/internal/testsanitizers" fails because FIPS 140 mode is
incompatible with ASAN.

Change-Id: I1a489f3398bbabf597fe7ffc0982c86c3b86e07e
Reviewed-on: https://go-review.googlesource.com/c/go/+/685495
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Quim Muntal <quimmuntal@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>