[12] RFR(S) 8196568: [Graal] LongMulOverflowTest.java fails with "runTestOverflow() did not overflow"

[Igor Veresov]

Exact math instrinsics in Graal are failing TCK. Since we’re out of time for 12, in order to make Graal compliant, I’d like to turn off emission of the floating exact math nodes. This fix is only for 12, and is not going upstream. For 13 I’ll work on a proper fix.

Webrev: http://cr.openjdk.java.net/~iveresov/8196568/webrev.00/
JBS: https://bugs.openjdk.java.net/browse/JDK-8196568


Thanks,
Igor