[11u] RFR (S) 8257513: C2: assert((constant_addr - _masm.code()->consts()->start()) == con.offset())

[Aleksey Shipilev]

Original bug:
   https://bugs.openjdk.java.net/browse/JDK-8257513
   https://git.openjdk.java.net/jdk/commit/8e42efaa

11u patch does not apply cleanly, because JDK-8240363 moved the affected code out of compile.cpp. I 
had to apply the hunks to the old locations.

11u variant:
   https://cr.openjdk.java.net/~shade/8257513/webrev.11u.01/

Testing: tier{1,2}; new regression test (fails without the product fix, passes with it)

-- 
Thanks,
-Aleksey