In go 1.11, go commands will use `GOFLAGS` as default flags, see
https://golang.org/doc/go1.11#go_command.
There is no need to pass GOFLAGS to $goflags, and if we do, go commands
will fail with "duplicate flags" error, e.g.
```
$ make test-integration WHAT=./test/integration/scheduler GOFLAGS="-v"
...
go test: v flag may be set only once
run "go help test" or "go help testflag" for more information
...
```
Automatic merge from submit-queue (batch tested with PRs 47921, 45984, 46829, 46896, 46923)
Remove unnecessary wrapper flags
**What this PR does / why we need it**:
Drop KUBE_GOFLAGS, KUBE_GOGCFLAGS, KUBE_GOLDFLAGS references
from the build infrastructure
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes#47296
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
This commit ensures that:
- go vet will be run as part of the make verify target
- the vet make-rule script won't be run directly, as generated_files won't be run in that case
- that go vet errors show up in the build log with a start time, finish time, and SUCCESS/FAILED message as part of the verify make rule script
Drop KUBE_GOFLAGS, KUBE_GOGCFLAGS, KUBE_GOLDFLAGS references
from the build infrastructure. There are some usages still
for KUBE_GOFLAGS, so we should print a deprecation message
until all those are fixed. If both KUBE_GOFLAGS and GOFLAGS
are just then we just bail out.
This allows us to start building real dependencies into Makefile.
Leave old hack/* scripts in place but advise to use 'make'. There are a few
rules that call things like 'go run' or 'build/*' that I left as-is for now.
Yecheng Fu