RFR: 8304915: Create jdk.internal.util.Architecture enum and apply [v10]

[Roger Riggs]

> Define an internal jdk.internal.util.Architecture enumeration and static methods to replace uses of the system property `os.arch`.
> The enumeration values are defined to match those used in the build.
> The initial values are: `X64, X86, AARCH64, RISCV64, S390, PPC64`
> Note that `amd64` and `x86_64` in the build are represented by `X64`.
> The value of the system property `os.arch` is unchanged.
> 
> The API is similar to the jdk.internal.util.OperatingSystem enum created by #[12931](https://git.openjdk.org/jdk/pull/12931).
> Uses in `java.base` and a few others are included but other modules will be done in separate PRs.

Roger Riggs has updated the pull request incrementally with one additional commit since the last revision:

  Modified test to check Architecture is64bits() and isLittleEndian()
  against Unsafe respective values.
  Relocated code mapping OS name and arch name from PlatformProps to
  OperatingSystem and Architecture. Kept the mapping of names
  in the template close to where the values are filled in by the build.

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/13357/files
  - new: https://git.openjdk.org/jdk/pull/13357/files/f3646dc9..fc40270a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13357&range=09
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13357&range=08-09

  Stats: 105 lines in 4 files changed: 46 ins; 41 del; 18 mod
  Patch: https://git.openjdk.org/jdk/pull/13357.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13357/head:pull/13357

PR: https://git.openjdk.org/jdk/pull/13357