Update vpnprofilestore_test to legacykeystore_test in TEST_MAPPING am: eeb6be2901 am: 4107fade78

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/cexpr/+/1756437

Change-Id: Id45934cc16af94d37f386a80347492b7efeeafbf