RFR: 8293999: [JVMCI] need support for aligned constants in generated code larger than 8 bytes [v3]

[Boris Ulasevich]

> 8293999: [JVMCI] need support for aligned constants in generated code larger than 8 bytes

Boris Ulasevich has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains two commits:

 - adding CodeSection._const_section_alignment field instead of 64 bytes alignment for all JVMCI nmethods
 - 8293999: [JVMCI] need support for aligned constants in generated code larger than 8 bytes

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Changes: https://git.openjdk.org/jdk/pull/10392/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10392&range=02
  Stats: 53 lines in 4 files changed: 26 ins; 20 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/10392.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10392/head:pull/10392

PR: https://git.openjdk.org/jdk/pull/10392