R1:b4f2cef76c96

Prevent interruption by the PHP "set_time_limit()" mechanism while holding the durable write lock

Summary:
Ref T13590. By default, PHP kills execution after web scripts run for 30 seconds. If this occurs in the locked section of a repository write while we're holding the durable write lock, the lock will get stuck.

Use "set_time_limit(0)" to prevent this mechanism from interrupting execution while the durable lock is held.

Test Plan:
- Added "set_time_limit(1)" before the lock and "while (1);" in the…