Enable debugRenderPhaseSideEffectsForStrictMode in test renderers (#31761)

This flag controls the strict mode double invoke render/lifecycles/etc
behavior in Strict Mode.

The only place this flag is off is the test renderers, which it should
be on for.

If we can land this, we can follow up to remove the flag.

packages/shared/forks/ReactFeatureFlags.test-renderer.js

@@ -10,7 +10,7 @@
 import typeof * as FeatureFlagsType from 'shared/ReactFeatureFlags';
 import typeof * as ExportsType from './ReactFeatureFlags.test-renderer';
 
-export const debugRenderPhaseSideEffectsForStrictMode = false;
+export const debugRenderPhaseSideEffectsForStrictMode = __DEV__;
 export const enableAsyncDebugInfo = false;
 export const enableSchedulingProfiler = false;
 export const enableProfilerTimer = __PROFILE__;

packages/shared/forks/ReactFeatureFlags.test-renderer.native-fb.js

@@ -11,7 +11,7 @@ import typeof * as FeatureFlagsType from 'shared/ReactFeatureFlags';
 import typeof * as ExportsType from './ReactFeatureFlags.test-renderer';
 
 export const alwaysThrottleRetries = false;
-export const debugRenderPhaseSideEffectsForStrictMode = false;
+export const debugRenderPhaseSideEffectsForStrictMode = __DEV__;
 export const disableClientCache = true;
 export const disableCommentsAsDOMContainers = true;
 export const disableDefaultPropsExceptForClasses = true;

packages/shared/forks/ReactFeatureFlags.test-renderer.www.js

@@ -10,7 +10,7 @@
 import typeof * as FeatureFlagsType from 'shared/ReactFeatureFlags';
 import typeof * as ExportsType from './ReactFeatureFlags.test-renderer.www';
 
-export const debugRenderPhaseSideEffectsForStrictMode = false;
+export const debugRenderPhaseSideEffectsForStrictMode = __DEV__;
 export const enableAsyncDebugInfo = false;
 export const enableSchedulingProfiler = false;
 export const enableProfilerTimer = __PROFILE__;