Revert "Change exception message for ArrayStoreException."

Fix all the libcore.java.lang.ArrayStoreExceptionTest failures. Why
are we pulling cosmetic changes from master?

This reverts commit 653ffbf481aa19c4f6c9a358b33d0d812758dfe5.

Change-Id: Icc4d1b40c578a5eef6890e9a03c7b10a96b75c0b