CipherTest: templatize OAEP tests

OAEP tests can be specified by using "OAEPPadding" or
"OAEPWith{hash}and{mgf}Padding", so make a helper function that creates
test cases for both.

Test: make -j32 build-art-host vogar && vogar --mode host --classpath out/host/common/obj/JAVA_LIBRARIES/core-tests-support-hostdex_intermediates/classes.jack --classpath out/host/common/obj/JAVA_LIBRARIES/core-tests-hostdex_intermediates/classes.jack libcore/luni/src/test/java/libcore/javax/crypto/CipherTest.java
Change-Id: I80710d864fb60b02dcaf1c39dab493bcf2d7b7e4