RFR: 8224240: Properties.load fails to throw IAE on malformed unicode in certain circumstances

[Claes Redestad]

Hi,

found a bug in Properties.load that apparently has been around since
Java 5. This patch adds proper bounds checking when decoding unicode
sequences.

Bug:    https://bugs.openjdk.java.net/browse/JDK-8224240
Webrev: http://cr.openjdk.java.net/~redestad/8224240/open.00

Since the fix means a behavior change in the error handling of certain
malformed property files, a CSR has been filed.

Thanks!

/Claes