Return BadRequest for invalid large patch

[liggitt]

What type of PR is this?

/kind bug
/kind failing-test

Which issue(s) this PR fixes:

Fixes #106573

Before https://github.com/kubernetes/kubernetes/pull/105916/files#diff-c4afbb7d6a8bdb1d6475f18abc92caa6c413f879aeeb189187c569f3f6c146f4L366, patches over 1kb were decoded before calling into the jsonpatch library, and any errors returned as a BadRequest.

Since go1.15, the stdlib decoder enforces the stackdepth limits, so we no longer need to do the pre-decode, but we need to treat a returned error decoding the patch as a bad request.

The failing tests were marked as long tests, so they don't run in presubmits, since they submit very large patches to the API server which can stress the presubmit env.

NONE

/cc @aojea @kevindelgado

[k8s-ci-robot]

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[liggitt]

/cc @apelisse

[aojea]

Since go1.15, the stdlib decoder enforces the stackdepth limits

heh seems you are familiar with it https://go-review.googlesource.com/c/go/+/199837

so, the test expects BadRequest but we are returning Invalid JSON Patch

kubernetes/test/integration/apiserver/max_request_body_bytes_test.go

Line 117 in ed07515

t.Errorf("expected success or bad request err, got %v", err)

kubernetes/staging/src/k8s.io/apiextensions-apiserver/test/integration/limit_test.go

Line 211 in ed07515

if !apierrors.IsBadRequest(err) {

/lgtm