RFR: 8266950: Remove vestigial support for non-strict floating-point execution [v8]

[David Holmes]

> As part of JEP 306, the vestiges of HotSpot support for non-strict floating-point execution can be removed. All methods implicitly have strictfp semantics so the explicit checks for is_strict() can be replaced by true and the code reformulated accordingly.
> 
> There are still some names that include "strict" that could potentially be renamed to remove it, but the fact we have to have strict fp semantics is still important on some platforms, so the names help reinforce that IMO.
> 
> Testing: tiers 1-3
> 
> Thanks,
> David

David Holmes has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 10 additional commits since the last revision:

 - Merge branch 'master' into jep-306
 - Merge branch 'master' into jep-306
 - Remove dead code on aarch64
 - Merge branch 'master' into jep-306
 - The code for strict handling only applies to doubles.
 - Add missing space
 - lir_div_strictfp and lir_mul_strictfp
 - Removed divDPR_reg_round as it has a false predicate and so is now unused
 - Revert classFileParser changes as they will be handled by JDK-8266530
 - 8266530: HotSpot changes for JEP 306
   All methods are now implicitly strictfp so all code generation etc
   uses the strict form.
   There are still some names that include "strict" that could potentially
   be renamed to rmeove it, but the fact we have to have strict fp semantics
   is still important on some platforms, so the names help reinforce that IMO.

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3991/files
  - new: https://git.openjdk.java.net/jdk/pull/3991/files/3ce17c29..d9015f58

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3991&range=07
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3991&range=06-07

  Stats: 23479 lines in 782 files changed: 3115 ins; 18957 del; 1407 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3991.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3991/head:pull/3991

PR: https://git.openjdk.java.net/jdk/pull/3991