runtime: skip TestTimePprof on sanitizers

runtime: skip TestTimePprof on sanitizers

This test asserts there is no external code, but the sanitizer runtimes
are external code.

Fixes #73783.

Cq-Include-Trybots: luci.golang.try:gotip-windows-amd64-race
Change-Id: I6a6a636cf93b7950e3ea35e00ec2eaf89911d712
Reviewed-on: https://go-review.googlesource.com/c/go/+/675296
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Auto-Submit: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>