RFR: The Grand ScopedValue renaming

[Andrew Haley]

Rename ExtentLocal to ScopedValue

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Commit messages:
 - The Grand ScopedValue renaming
 - Grammar fixups
 - Extent.local exact matches
 - extent.local exact matches
 - extentLocal exact matches
 - Rename files
 - ExtentLocal exact matches
 - Merge https://github.com/openjdk/loom into fibers
 - Merge https://github.com/openjdk/loom into fibers
 - Merge https://github.com/openjdk/loom into fibers
 - ... and 32 more: https://git.openjdk.org/loom/compare/ec79c3f4...521b9056

Changes: https://git.openjdk.org/loom/pull/192/files
 Webrev: https://webrevs.openjdk.org/?repo=loom&pr=192&range=00
  Stats: 4373 lines in 54 files changed: 2089 ins; 2089 del; 195 mod
  Patch: https://git.openjdk.org/loom/pull/192.diff
  Fetch: git fetch https://git.openjdk.org/loom pull/192/head:pull/192

PR: https://git.openjdk.org/loom/pull/192