RFR: CODETOOLS-7902927: JMH: Support HTML flamegraphs for async-profiler [v3]

[Aleksey Shipilev]

> Turns out, newer async-profiler silently eats "-o svg", expecting "-o flamegraph". It now generates HTML flamegraphs too. We need to handle both new and old flamegraph styles.
> 
> Additional testing:
>  - [x] Self-built async-profiler 2.0
>  - [x] Self-built async-profiler 1.8.5
>  - [x] Released async-profiler 2.0
>  - [x] Released async-profiler 1.8.5

Aleksey Shipilev has updated the pull request incrementally with two additional commits since the last revision:

 - Make sure to capture only "1.", not just "1"
 - Even simpler

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Changes:
  - all: https://git.openjdk.java.net/jmh/pull/36/files
  - new: https://git.openjdk.java.net/jmh/pull/36/files/a77ff455..7916f232

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jmh&pr=36&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jmh&pr=36&range=01-02

  Stats: 62 lines in 2 files changed: 0 ins; 57 del; 5 mod
  Patch: https://git.openjdk.java.net/jmh/pull/36.diff
  Fetch: git fetch https://git.openjdk.java.net/jmh pull/36/head:pull/36

PR: https://git.openjdk.java.net/jmh/pull/36