[8u] RFR + RFA: 8213419: "C2 may hang in MulLNode::Ideal()/MulINode::Ideal() with gcc 8.2.1" and follow up 8214206

[Roland Westrelin]

> Changes look good.

Thanks for the reviews.

> Where's the regression test? MultiplyByIntegerMinHang.java is in original change.

Good catch. I forgot to "hg add" the test:

http://cr.openjdk.java.net/~roland/8213419.8u/webrev.01/

Roland.