For some dependencies, like stubs, the SDK library may not be found at
build time (either because the implementation library is not among the
dependencies of the dexpreopted module, or because it's part of a
prebuilt, or because it's missing from the build altogether). In such
cases dexpreopt is useless, because dex2oat does not have access to the
full classpath (unless the &-classpath is used). Therefore do not
dexpreopt in such cases.
Test: lunch aosp_cf_x86_phone-userdebug && m
Bug: 132357300
Change-Id: If289088cfd103011ccb16165e95a97b30fd31b81
fc24ad3d4e