Add a command line option to optimize individual splits

The new option is "--split SplitName" and applies to "adb shell cmd
package compile" command.

Usage example:
adb shell cmd package compile -m speed --split split_feature_a.apk
com.android.cts.classloadersplitapp

Bug: 38138251

Test: adb install-multiple CtsClassloaderSplitApp.apk
CtsClassloaderSplitAppFeatureA.apk CtsClassloaderSplitAppFeatureB.apk
      adb shell cmd package compile -m speed --split split_feature_a.apk
com.android.cts.classloadersplitapp
      check the status of split_feature_a
      runtest -x
services/tests/servicestests/src/com/android/server/pm/dex/DexoptOptionsTests.java

Change-Id: I579bb12fa6699f99cd3824f185bd9352fb8007c5