[11u] 8229495: SIGILL in C2 generated OSR compilation

[Roland Westrelin]

Original bug:
  https://bugs.openjdk.java.net/browse/JDK-8229495
  https://hg.openjdk.java.net/jdk/jdk15/rev/c973b5ec934d
  
Original patch does not apply cleanly to 11u (different context in
loopTransform.cpp, loopnode.cpp, node.hpp) but the 11u patch is
identical to the original patch (except for a change related to node
budget handling which doesn't exist in 11).
 
11u webrev:
  http://cr.openjdk.java.net/~roland/8229495.11u/webrev.00/
 
Testing: x86_64 build, tier1. The test case passes with and without the
patch (I noticed when working on the upstream fix that that test case is
fragile so it's not unexpected).
 
Roland.