[foreign-jextract] RFR: 8273382: jextract should generete alias layout for pointer typedefs

[Athijegannathan Sundararajan]

Generating C_POINTER layout variables for pointer typedefs in the header

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Commit messages:
 - whitespace removed in TypeImpl.java
 - 8273382: jextract should generete alias layout for pointer typedefs

Changes: https://git.openjdk.java.net/panama-foreign/pull/575/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=575&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8273382
  Stats: 78 lines in 6 files changed: 73 ins; 1 del; 4 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/575.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/575/head:pull/575

PR: https://git.openjdk.java.net/panama-foreign/pull/575