Revert "cmd/compile: enable Asan check for global variables"

Revert "cmd/compile: enable Asan check for global variables"

This reverts CL 321715.

Reason for revert: broke cmd/go.TestScript/install_msan_and_race_require_cgo on several builders.

Change-Id: Ia0392de555d6e973960769a0e4709f0193d16706
Reviewed-on: https://go-review.googlesource.com/c/go/+/401755
Run-TryBot: Bryan Mills <bcmills@google.com>
Auto-Submit: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>