RFR: 8266252: Streamline AbstractInterpreter::method_kind [v2]

[Claes Redestad]

> This patch refactors AbstractInterpreter::method_kind to reduce branches on average while better compartmentalizing the exceptional cases.
> 
> Additionally Method::is_empty_method is trivial enough that making it inlineable helps reduce cost while reducing size of the libjvm.
> 
> Result is a 40% speed-up, or a reduction of .25% of instructions on Hello World that scales to larger applications.

Claes Redestad has updated the pull request incrementally with one additional commit since the last revision:

  assert that vmIntrinsics::_dsqrt are only selected for Math/StrictMath::sqrt

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3798/files
  - new: https://git.openjdk.java.net/jdk/pull/3798/files/4f7ea902..4e616b33

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3798&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3798&range=00-01

  Stats: 7 lines in 1 file changed: 4 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3798.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3798/head:pull/3798

PR: https://git.openjdk.java.net/jdk/pull/3798