Add -only-out-test-toml flag (#3881)

## Summary

This PR:
1. Adds a new flag to the acceptance test framework that allows
regenerating `out.test.toml` configuration files without running the
actual tests, making it much faster to update test configurations.

## Usage

### Using Make target (recommended)
```bash
make generate-out-test-toml
```

Author: shreyas-goenka

Makefile

@@ -87,6 +87,10 @@ test-update:
 test-update-templates:
 	-go test ./acceptance -run '^TestAccept/bundle/templates' -update -timeout=${LOCAL_TIMEOUT}
 
+# Regenerate out.test.toml files without running tests
+generate-out-test-toml:
+	go test ./acceptance -run '^TestAccept$$' -only-out-test-toml -timeout=${LOCAL_TIMEOUT}
+
 # Updates acceptance test output (integration tests, requires access)
 test-update-aws:
 	deco env run -i -n aws-prod-ucws -- go test ./acceptance -run ^TestAccept$$ -update -timeout=1h -skiplocal -v
@@ -167,7 +171,7 @@ generate:
 	$(GENKIT_BINARY) update-sdk
 
 
-.PHONY: lint lintfull tidy lintcheck fmt fmtfull test test-unit test-acc test-slow test-slow-unit test-slow-acc cover showcover build snapshot snapshot-release schema integration integration-short acc-cover acc-showcover docs ws wsfix links checks test-update test-update-templates test-update-aws test-update-all generate-validation
+.PHONY: lint lintfull tidy lintcheck fmt fmtfull test test-unit test-acc test-slow test-slow-unit test-slow-acc cover showcover build snapshot snapshot-release schema integration integration-short acc-cover acc-showcover docs ws wsfix links checks test-update test-update-templates generate-out-test-toml test-update-aws test-update-all generate-validation
 
 test-exp-aitools:
 	make test TEST_PACKAGES="./experimental/aitools/..." ACCEPTANCE_TEST_FILTER="TestAccept/idontexistyet/aitools"

acceptance/acceptance_test.go

@@ -48,6 +48,7 @@ var (
 	UseVersion      string
 	WorkspaceTmpDir bool
 	TerraformDir    string
+	OnlyOutTestToml bool
 )
 
 // In order to debug CLI running under acceptance test, search for TestInprocessMode and update
@@ -78,6 +79,7 @@ func init() {
 	// creates these symlinks when a file_mirror is used for a provider (in .terraformrc). This flag
 	// allows us to download the provider to the workspace file system on DBR enabling DBR integration testing.
 	flag.StringVar(&TerraformDir, "terraform-dir", "", "Directory to download the terraform provider to")
+	flag.BoolVar(&OnlyOutTestToml, "only-out-test-toml", false, "Only regenerate out.test.toml files without running tests")
 }
 
 const (
@@ -307,14 +309,19 @@ func testAccept(t *testing.T, inprocessMode bool, singleTest string) int {
 			config, configPath := internal.LoadConfig(t, dir)
 			skipReason := getSkipReason(&config, configPath)
 
-			if testdiff.OverwriteMode {
+			if testdiff.OverwriteMode || OnlyOutTestToml {
 				// Generate materialized config for this test
 				// We do this before skipping the test, so the configs are generated for all tests.
 				materializedConfig, err := internal.GenerateMaterializedConfig(config)
 				require.NoError(t, err)
 				testutil.WriteFile(t, filepath.Join(dir, internal.MaterializedConfigFile), materializedConfig)
 			}
 
+			// If only regenerating out.test.toml, skip the actual test execution
+			if OnlyOutTestToml {
+				t.Skip("Skipping test execution (only regenerating out.test.toml)")
+			}
+
 			if skipReason != "" {
 				skippedDirs += 1
 				t.Skip(skipReason)