pkg/cvo/cvo_test: Firm up Test_gateApplicableToCurrentVersion checking

This code is from 519b466 (Bug 1978376: Add admin ack Upgradeable
condition gate, 2021-07-27, #633).  But I'm about to move it, and
CodeRabbit complains about the unhandled "wantErr=true, but err==nil"
and "expectedResult=true but isApplicable=false" situations.  Extend
the logic to check for those.

Also move from t.Fatal* to t.Error*, because there's no harm in moving
on to check the other condition, even if the first condition we check
has a problem.  Checking both will give the developer more information
about what they need to fix to make the test happy, without them
needing to retest after fixing one property before they hear about a
problem with the other property.

[1]: #1368 (comment)

Author: wking

pkg/cvo/cvo_test.go

@@ -4000,14 +4000,13 @@ func Test_gateApplicableToCurrentVersion(t *testing.T) {
 		{
 			t.Run(tt.name, func(t *testing.T) {
 				isApplicable, err := gateApplicableToCurrentVersion(tt.gateName, tt.cv)
-				if err != nil && !tt.wantErr {
-					t.Fatalf("gateApplicableToCurrentVersion() unexpected error: %v", err)
+				if isApplicable != tt.expectedResult {
+					t.Errorf("gateApplicableToCurrentVersion() %s expected applicable %t, got applicable %t", tt.gateName, tt.expectedResult, isApplicable)
 				}
-				if err != nil {
-					return
-				}
-				if isApplicable && !tt.expectedResult {
-					t.Fatalf("gateApplicableToCurrentVersion() %s should not apply", tt.gateName)
+				if err != nil && !tt.wantErr {
+					t.Errorf("gateApplicableToCurrentVersion() unexpected error: %v", err)
+				} else if err == nil && tt.wantErr {
+					t.Error("gateApplicableToCurrentVersion() unexpected success when an error was expected")
 				}
 			})
 		}