RFR: Stop compiling old oopMapStubGenerator

[Aleksey Shipilev]

This code is currently not used, and it might not be used in future too. There is no way to test if it works, currently. It is the major source of build failure when compiling x86_32. So, it would be better to `#if 0` it, or even remove it wholesale.

Additional testing:
 - [x] Linux x86_64 `tier1_loom`

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Commit messages:
 - Newlines
 - Stop compiling old oopMapStubGenerator

Changes: https://git.openjdk.java.net/loom/pull/66/files
 Webrev: https://webrevs.openjdk.java.net/?repo=loom&pr=66&range=00
  Stats: 15 lines in 5 files changed: 12 ins; 3 del; 0 mod
  Patch: https://git.openjdk.java.net/loom/pull/66.diff
  Fetch: git fetch https://git.openjdk.java.net/loom pull/66/head:pull/66

PR: https://git.openjdk.java.net/loom/pull/66