RFR: 8294578: [PPC64] C2: Missing is_oop information when using disjoint compressed oops mode [v2]

[Martin Doerr]

> Fix missing is_oop information shown by assertion `assert(t->base() == Type::Int || t->base() == Type::Half || t->base() == Type::FloatCon || t->base() == Type::FloatBot) failed: Unexpected type`. See JBS issue for details.

Martin Doerr has updated the pull request incrementally with one additional commit since the last revision:

  Revert decodeN_Disjoint_isel_Ex part. Not needed.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/10484/files
  - new: https://git.openjdk.org/jdk/pull/10484/files/e409d040..9d14323b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10484&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10484&range=00-01

  Stats: 5 lines in 1 file changed: 2 ins; 3 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/10484.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10484/head:pull/10484

PR: https://git.openjdk.org/jdk/pull/10484