Address kyaml windows compatibility issues

kyaml/fn/runtime/container/container_test.go

@@ -197,7 +197,10 @@ func TestFilter_ExitCode(t *testing.T) {
 		t.FailNow()
 	}
 
-	if !assert.EqualError(t, instance.GetExit(), "fork/exec /not/real/command: no such file or directory") {
+	if !assert.Error(t, instance.GetExit()) {
+		t.FailNow()
+	}
+	if !assert.Contains(t, instance.GetExit().Error(), "/not/real/command") {
 		t.FailNow()
 	}
 }

kyaml/fn/runtime/runtimeutil/runtimeutil_test.go

@@ -426,7 +426,7 @@ metadata:
 
 		{
 			name:              "write_results_bad_results_file",
-			expectedError:     "open /not/real/file: no such file or directory",
+			expectedError:     "open /not/real/file:",
 			noMakeResultsFile: true,
 			run: testRun{
 				output: `
@@ -1048,7 +1048,10 @@ metadata:
 			}
 			output, err := tt.instance.Filter(inputs)
 			if tt.expectedError != "" {
-				if !assert.EqualError(t, err, tt.expectedError) {
+				if !assert.Error(t, err) {
+					t.FailNow()
+				}
+				if !assert.Contains(t, err.Error(), tt.expectedError) {
 					t.FailNow()
 				}
 				return

kyaml/fn/runtime/starlark/starlark_test.go

@@ -481,7 +481,6 @@ spec:
 	for i := range tests {
 		test := tests[i]
 		t.Run(test.name, func(t *testing.T) {
-			os.Clearenv()
 			for k, v := range test.env {
 				os.Setenv(k, v)
 			}