RFR: 8276215: Intrinsics matchers should handle native method flags better

[Aleksey Shipilev]

Found this while working on JDK-8276096. It seems when the actual method is native, `F_R` (regular) intrinsic definition still matches. I believe that happens because flag matchers check for native flags only optionally. It would be better to implement this more consistently. This requires a few simple adjustments to current intrinsics definitions. #6184 handled a larger `StrictMath` oddity.

Additional testing:
 - [x] Linux x86_64 fastdebug `tier1`
 - [x] Linux x86_64 fastdebug `tier2`
 - [x] Linux x86_64 fastdebug `applications/ctw/modules` (which has a nice side-effect of touching a lot of JDK methods)

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Commit messages:
 - Fix

Changes: https://git.openjdk.java.net/jdk/pull/6187/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6187&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8276215
  Stats: 79 lines in 2 files changed: 50 ins; 0 del; 29 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6187.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6187/head:pull/6187

PR: https://git.openjdk.java.net/jdk/pull/6187