RFR: 8273239: Standardize Ticks APIs return type [v2]

[Albert Mingkun Yang]

> Simple change on return types of Ticks API.
> 
> The call of `milliseconds()` in `spinYield.cpp` seems a bug to me, because the unit in the message is `usecs`. Therefore, I changed it to `microseconds()`.
> 
> Test: tier1

Albert Mingkun Yang has updated the pull request incrementally with one additional commit since the last revision:

  template

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5332/files
  - new: https://git.openjdk.java.net/jdk/pull/5332/files/faceab9a..2fab83d6

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5332&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5332&range=00-01

  Stats: 152 lines in 7 files changed: 75 ins; 53 del; 24 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5332.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5332/head:pull/5332

PR: https://git.openjdk.java.net/jdk/pull/5332