RFR: 8320128: Clean up Parse constructor for OSR [v2]

[Xin Liu]

> There's a special case for the constructor of Parse. If current compilation is OSR and it is handling the top-level method(depth() == 1), then
> 
> 1. _tf = C->tf();
> 2. _entry_bci = C->entry_bci();
> 3. _flow = method()->get_osr_flow_analysis(_entry_bci);
> 
> We don't need to assign those member data twice. We can also factor out _flow->failing() for the special case and normal cases. 
> 
> It's worth mentioning that we can't save ciTypeFlow computation because
> get_osr_flow_analysis(_entry_bci) actually needs get_flow_analysis(method()).

Xin Liu has updated the pull request incrementally with one additional commit since the last revision:

  Update according to reviewer's feedback.

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/16669/files
  - new: https://git.openjdk.org/jdk/pull/16669/files/df8eb6e2..1f7c956c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16669&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16669&range=00-01

  Stats: 13 lines in 2 files changed: 4 ins; 2 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/16669.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16669/head:pull/16669

PR: https://git.openjdk.org/jdk/pull/16669