Run dexopt asynchronously

The dexopt may take more than 10 mins but watchdog will be triggered
if installation took 10 mins. To avoid watchdog timeout, runs dexopt
asynchronously.

Bug: 388159696
Flag: EXEMPT bug fix
Test: atest CtsPackageInstallTestCases
Test: atest CtsInstallHostTestCases
Change-Id: I968843a192ffc39ef37959019e148c747e65e472