[foreign-memaccess+abi] RFR: 8266627: CLinker allocateMemory, freeMemory implementation should not use default lookup

[Maurizio Cimadamore]

This patch removes the workaround on Windows which requires loading msvcrt.dll.

The solution is to create (Java side) a memory segment and fill it with function pointers on the VM side.
This way, Java code can look up VM functions easily. I've moved this support onto a different class, as the approach might, in the future, be required for other VM functions.

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Commit messages:
 - Initial push

Changes: https://git.openjdk.java.net/panama-foreign/pull/527/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=527&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8266627
  Stats: 147 lines in 3 files changed: 122 ins; 23 del; 2 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/527.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/527/head:pull/527

PR: https://git.openjdk.java.net/panama-foreign/pull/527