cmd/cue: add get go test case with the new omitzero json tag

This shows the current behavior with the new field tag added
in Go 1.24, which is an improvement over omitempty.
The following commit will tweak the behavior.

For #3869.

Signed-off-by: Daniel Martí <[email protected]>
Change-Id: I4554cb7d7dec9a59f459768427dce5c2b50a246e
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1213250
TryBot-Result: CUEcueckoo <[email protected]>
Unity-Result: CUE porcuepine <[email protected]>
Reviewed-by: Roger Peppe <[email protected]>

Author: mvdan

Diff for: cmd/cue/cmd/testdata/script/get_go_types.txtar

@@ -108,6 +108,8 @@ type Foozer struct {
 
 	OptionalOmitEmptyJSON string `json:"optionalOmitEmptyJSON,omitempty"`
 
+	OptionalOmitZeroJSON time.Time `json:"optionalOmitZeroJSON,omitzero"`
+
 	OptionalOmitEmptyYAML string `yaml:"optionalOmitEmptyYAML,omitempty"`
 
 	// +optional
@@ -328,8 +330,9 @@ import (
 	Embed: {
 		CustomJSON: #CustomJSON
 	} @go(,struct{CustomJSON})
-	optionalOmitEmptyJSON?: string @go(OptionalOmitEmptyJSON)
-	optionalOmitEmptyYAML?: string @go(OptionalOmitEmptyYAML)
+	optionalOmitEmptyJSON?: string    @go(OptionalOmitEmptyJSON)
+	optionalOmitZeroJSON:   time.Time @go(OptionalOmitZeroJSON)
+	optionalOmitEmptyYAML?: string    @go(OptionalOmitEmptyYAML)
 
 	// +optional
 	optionalComment?: string @go(OptionalComment)