RFR: 8256862: Several java/foreign tests fail on x86_32 platforms

[Jorn Vernee]

This patch fixes several failures on x86_32 of java/foreign tests.

This is mostly done by disabling the failing tests, but the impl of CLinker is also adjusted ton properly detect 32 bit platforms as unsupported.

CLinker is specified to fail in the initializer on unsupported platforms, and a test is added to verify this as well.

Note that this adds requires clauses to the failing tests that explicitly enumerate all available platforms, so this should fix the test failures on other platforms as well.

https://bugs.openjdk.java.net/browse/JDK-8256757 is filed for the remaining failure in TestStringLatin1IndexOfChar.

CSR link: https://bugs.openjdk.java.net/browse/JDK-8256863

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Commit messages:
 - Enumerate supported platforms specifically in requires tags
 - Clarify CLinker statement about unsupported platforms
 - - Add negative test for 32-bit platform.

Changes: https://git.openjdk.java.net/jdk/pull/1386/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1386&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8256862
  Stats: 94 lines in 20 files changed: 83 ins; 0 del; 11 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1386.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1386/head:pull/1386

PR: https://git.openjdk.java.net/jdk/pull/1386