Replace broken --wait flag with --wait-for-staged-ready flag

Read b/158314277#2 to understand how the flag got broken.

Since both streaming install and staged install are using --wait flag,
we need to change one of them to avoid conflict. We decided to change
the generic --wait flag for staged install to something more specific
like --wait-for-ready to avoid future conflicts.

Also added some internal test so that we can catch broken shell commands
sooner.

While at it, added test for --no-wait flag and install-multi-package
command too.

Bug: 158314277
Test: atest StagedInstallInternalTest#testAdbStagedInstallWaitForReadyFlagWorks
Test: atest StagedInstallInternalTest#testAdbStagedInstallNoWaitFlagWorks
Change-Id: I8d2d0db56a00cfffc942963c3ee72464ea770c88