RFR: 8219229: Make ConstantPool::tag_at and release_tag_at_put inlineable

[Claes Redestad]

Hi,

JDK-8191102 moved tag_at and release_tag_at_put from constantPool.hpp to
constantPool.cpp. These now outlined methods show up in startup
profiles, especially when the bytecode verifier is enabled.

Moving these trivial methods (and some .hpp-defined methods they rely
on) to constantPool.inline.hpp helps inlining and measurably improves
timings in various startup benchmarks, while remaining footprint
neutral. The patch also weeds out a few places where we were relying on
an implicit include of constantPool.hpp.

Webrev: http://cr.openjdk.java.net/~redestad/8219229/open.00/
Bug:    https://bugs.openjdk.java.net/browse/JDK-8219229

Test: tier1+2

Thanks!

/Claes