This commit corrects a race condition in the RealtimeSchedulerTest. The
fix ensures that when the TestHandler processes a message, it first adds
the message to the executionTimes before calling cv.open(). This change
guarantees the correct order of operations and prevents potential
synchronization issues.
Test: TH
Bug: 403413950
Flag: EXEMPT bugfix
Change-Id: I16dee5475db315b1b40d0779db4ff31407bf54b5
428d25ceac