[8u40] RFR(s): backport of 8035328 and 8044538

[Tobias Hartmann]

Hi,

please review the following backports to 8u40.

8035328: closed/compiler/6595044/Main.java failed with timeout
https://bugs.openjdk.java.net/browse/JDK-8035328
http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/46e85b1633d7
http://cr.openjdk.java.net/~thartmann/8035328/webrev.00/

8044538: assert(which != imm_operand) failed: instruction is not a movq 
reg, imm64
https://bugs.openjdk.java.net/browse/JDK-8044538
http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/f3624d042de0
http://cr.openjdk.java.net/~thartmann/8044538/webrev.04/

The changes were pushed to 9 some weeks ago and nightly testing showed 
no problems. All changes apply cleanly to 8u40.

Thanks,
Tobias