[code-reflection] RFR: Null check only when selector expression of switch expression is of reference type [v3]

[Mourad Abbay]

> Generate lowered form of switch expression that check if the selector expression is null only when the selector expression has type reference.

Mourad Abbay has updated the pull request incrementally with two additional commits since the last revision:

 - Remove unnecessary import
 - Add missing import

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Changes:
  - all: https://git.openjdk.org/babylon/pull/112/files
  - new: https://git.openjdk.org/babylon/pull/112/files/b01ba094..2217d973

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=babylon&pr=112&range=02
 - incr: https://webrevs.openjdk.org/?repo=babylon&pr=112&range=01-02

  Stats: 2 lines in 2 files changed: 0 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/babylon/pull/112.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/112/head:pull/112

PR: https://git.openjdk.org/babylon/pull/112