RFR: Merge jdk:master

[Kevin Rushforth]

Manual merge of `jdk/master` into `lanai/master` since the nightly auto-merge process is still offline (see [SKARA-764](https://bugs.openjdk.java.net/browse/SKARA-764)).

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Commit messages:
 - Merge jdk:master
 - 8255287: aarch64: fix SVE patterns for vector shift count
 - 8255340: [s390] build failure after JDK-8255208
 - 8255129: [PPC64, s390] Check vector_size_supported and add VectorReinterpret node
 - 8255274: [PPC64, s390] wrong StringLatin1.indexOf version matched
 - 8254982: (tz) Upgrade time-zone data to tzdata2020c
 - 8254670: SVE test uses linux-specific api
 - 8254286: Wrong inference in switch expression with "null" arm
 - 8249675: x86: frequency extraction from cpu brand string is incomplete
 - 8255067: Restore Copyright line in file modified by 8253191
 - ... and 137 more: https://git.openjdk.java.net/lanai/compare/fbc066e0...5028b5c0

The webrevs contain the adjustments done while merging with regards to each parent branch:
 - master: https://webrevs.openjdk.java.net/?repo=lanai&pr=122&range=00.0
 - jdk:master: https://webrevs.openjdk.java.net/?repo=lanai&pr=122&range=00.1

Changes: https://git.openjdk.java.net/lanai/pull/122/files
  Stats: 64282 lines in 854 files changed: 48431 ins; 11985 del; 3866 mod
  Patch: https://git.openjdk.java.net/lanai/pull/122.diff
  Fetch: git fetch https://git.openjdk.java.net/lanai pull/122/head:pull/122

PR: https://git.openjdk.java.net/lanai/pull/122