RFR (XS) 8217344 : Make comparison overflow-aware in ECDHKeyAgreement.engineGenerateSecret()

[Ivan Gerasimov]

Hello!

Would you please help review a trivial fix to avoid a possible 
arithmetic overflow in comparison?

BUGURL: https://bugs.openjdk.java.net/browse/JDK-8217344
WEBREV: http://cr.openjdk.java.net/~igerasim/8217344/00/webrev/

Thanks in advance!

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With kind regards,
Ivan Gerasimov