KeyMint VTS: require curve for ECDSA keys

The KeyMint AIDL spec requires that "Tag::EC_CURVE must be provided to
generate an ECDSA key". Move the VTS tests to always create ECDSA keys
by curve not key size.

Bug: 188672564
Test: VtsAidlKeyMintTargetTest
Change-Id: I33036387c243b21ab0ecd49221b7e7757598913e
3 files changed