RFR: 8303415: Add VM_Version::is_intrinsic_supported(id) [v2]

[Vladimir Kozlov]

> Currently we check VM flags, directives and JIT compiler support when we generate intrinsics. 
> We have *product* VM flags for most intrinsics and set them in VM based on HW support. 
> But not all intrinsics have such flags and it is not scalable to add new *product* flag for each new intrinsic. 
> Also we have `-XX:DisableIntrinsic=<id>` and `-XX:ControlIntrinsic=<id>` flags to control intrinsics from command line. We don't need specific flags for that. 
> 
> I propose to add new `VM_Version::is_intrinsic_supported(id)` method to check platform support for intrinsic without adding new flag. I used it for `_floatToFloat16` intrinsic for my work on [JDK-8302976](https://bugs.openjdk.org/browse/JDK-8302976).
> 
> Additional fixes:
> Fixed Interpreter to skip intrinsics if they are disabled with flag.
> Moved Interpreter's `InlineIntrinsics` flag check into one place in shared code.
> Added separate interpreter id for `_dsqrt_strict` so it could be disabled separately from regular `_dsqrt`.
> Added missing `native` mark to `_currentThread`.
> Removed unused `AbstractInterpreter::in_native_entry()`.
> Cleanup C2 intrinsic checks code.
> 
> Tested tier1-4,xcomp,stress. Also ran tier1-3,xcomp with `-XX:-InlineIntrinsics`.

Vladimir Kozlov has updated the pull request incrementally with one additional commit since the last revision:

  Address comments

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/12858/files
  - new: https://git.openjdk.org/jdk/pull/12858/files/43c0056b..2d6ff556

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12858&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12858&range=00-01

  Stats: 28 lines in 4 files changed: 4 ins; 21 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/12858.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12858/head:pull/12858

PR: https://git.openjdk.org/jdk/pull/12858