This is only a test fix for lock_stats_suboperation_curop.js on mobile platform.
lock_stats_suboperation_curop.js uses assert.soon and currentOp() to make sure index build has started and then checks the 'lockStats' section for 'timeAcquiringMicros'. However, there is a very small time window between the time currentOp() catches the index build and index build takes the lock. In this scenario, the test would find 'lockStats' section being empty.
To fix this, assert.soon should wait until all the locks are held.