[foreign-jextract] RFR: 8261893: jextract generates class names that are restricted type names

[Athijegannathan Sundararajan]

a table of restricted type names is checked.

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Commit messages:
 - 8261893: jextract generates class names that are restricted type names

Changes: https://git.openjdk.java.net/panama-foreign/pull/453/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=453&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8261893
  Stats: 106 lines in 3 files changed: 105 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/453.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/453/head:pull/453

PR: https://git.openjdk.java.net/panama-foreign/pull/453