Fix deadlock in Java Cloud Debugger when the debugger is disabled and re-enabled immediately.
Fix deadlock in Java Cloud Debugger when the debugger is disabled and re-enabled immediately.

This situation only occurs in the component test. The debugger never gets dynamically disabled in production environment.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=111712162

GoogleCloudPlatform/cloud-debug-java,GoogleCloudPlatform/cloud-debug-java,GoogleCloudPlatform/cloud-debug-java,GoogleCloudPlatform/cloud-debug-java