RFR: 8247747: Remove macro definition of "inline" in stack.hpp

[Kim Barrett]

Please review this change to the Stack utility class, removing the
definition of "inline" as a macro with an empty expansion.  I also
made a couple micro-optimizations to the push and pop functions, and
made pop_segment NOINLINE, being consistent with the similar slow path
push_segment.

Making this change didn't produce any measurable difference in the
performance tests I ran.  This suggests the overflow part of the task
queues is either not *too* heavily used, or maybe the effect of this
is being drowned by other costs.

CR:
https://bugs.openjdk.java.net/browse/JDK-8247747

Webrev:
https://cr.openjdk.java.net/~kbarrett/8247747/open.00/

Testing:
mach5 tier1