Disable dexpreopt if optional_uses_libs does not have an impl

At ToT, an optional_uses_libs is not added to the build time CLC if it
does not exist in the tree. One edge case here is
java_sdk_library_import, which might exist in the tree, but without an
implementation. This cause issues during analysis when we try to verify
the correctness of the build time CLC.

This CL disables dexpreopt if a dependency does not have an
implementation. To limit inadvertent side effects, this is restricted to
java_sdk_library(_import) module types. (more precisely, it is restricted
to java_sdk_library_import, since the source module type will always
have an impl)

Bug: 315802285
Test: Added a unit test
Test: m nothing
Test: printf debugging in internal main, verified that this CL does not
disable dexpreopt on any android app inadvertently

Change-Id: I173fc2f3ff654fe4091e9a43322164afd3222ee7