[foreign-memaccess+abi] RFR: 8263459: Add better support for restricted methods

[Athijegannathan Sundararajan]

When a Panama native restricted method is called, we will no require that the caller module (which could be ALL-UNNAMED) has been whitelisted accordingly, on the command line, using this flag:

--enable-native-access=<modulename>

In other words, this work replaces the hacky -Dforeign.restricted=permit property with a system which works in tandem with the Java module system.

The current PR includes subset of the earlier PR 

https://github.com/openjdk/panama-foreign/pull/471

The 'fail fast' aspect (jlink plugin to mark "NativeAccess" calling modules and issuing error if those modules were not mentioned in --enable-native-access) has been removed in this new PR.

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Commit messages:
 - trailing whitespace removal
 - Merge remote-tracking branch 'origin/foreign-memaccess+abi' into JDK-8263459-minimal
 - 8263459: Add better support for restricted methods

Changes: https://git.openjdk.java.net/panama-foreign/pull/472/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=472&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8263459
  Stats: 891 lines in 73 files changed: 803 ins; 43 del; 45 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/472.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/472/head:pull/472

PR: https://git.openjdk.java.net/panama-foreign/pull/472