Fix: Conditionally remove atb from bootclasspath for core_tiny.xml

Seems to be a cut-and-paste error in ag/3520851
base and core_minimal use REMOVE_ATB_FROM_BCP,
core_tiny used REMOVE_OAHL_FROM_BCP
(cut and pasted from the section above for
framework-oahl-backward-compatibility)

Bug: 74074575
Bug: 30188076
Test: no more of the following on wear:
  Unable to open boot classpath entry: /system/framework/framework-atb-backward-compatibility.jar
Signed-off-by: Ben Fennema <fennema@google.com>

Change-Id: I25327705ff37ab3d077b3917fcca096c398eb3ee