RFR: 8286393: Address possibly lossy conversions in java.rmi

[Roger Riggs]

Updates to modules java.rmi and java.smartcardio to remove warnings about lossy-conversions introduced by PR#8599.

Explicit casts are inserted where implicit casts occur.

8286393: Address possibly lossy conversions in java.rmi
8286388: Address possibly lossy conversions in java.smartcardio

-------------

Commit messages:
 - 8286393: Address possibly lossy conversions in java.rmi

Changes: https://git.openjdk.java.net/jdk/pull/8683/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8683&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8286393
  Stats: 6 lines in 2 files changed: 0 ins; 0 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8683.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8683/head:pull/8683

PR: https://git.openjdk.java.net/jdk/pull/8683