RFR(XS): 8246023: Obsolete LIRFillDelaySlot

[Mikael Vidstedt]

Please review this small change which obsoletes the LIRFillDelaySlot flag:

JBS: https://bugs.openjdk.java.net/browse/JDK-8246023
webrev: https://cr.openjdk.java.net/~mikael/webrevs/8246023/webrev.00/open/webrev
CSR: https://bugs.openjdk.java.net/browse/JDK-8246024

Background (from JBS):

With SPARC removed (JDK-8241787) the LIRFillDelaySlot flag no longer has any relevant effect and should be removed using the normal process. Since the flag was really only useful on SPARC and since all the code it once controlled is now gone the flag will go directly to obsolete, skipping the deprecation step.

Testing:

* Manual verification running with the flag: spits out the warning as expected
* tier1: in progress


Note: I believe additional cleanup is possible related to delay slots, but I’d like to handle that separately.

Cheers,
Mikael