[jdk16] RFR: 8257919: [JVMCI] profiling info didn't change after reprofile

[Vladimir Ivanov]

JDK-8252049 moved compiler counter initialization into MethodData constructor, but JVMCI and WhiteBox API rely on `MethodData::initialize()`/`MethodData::init()` to reset MDO state. 

Proposed fix restores the logic which resets the counters in `init()` (which is called from `initialize()`).

Testing:
- [x] hs-precheckin-comp, hs-tier1, hs-tier2

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Commit messages:
 - 8257919: [JVMCI] profiling info didn't change after reprofile

Changes: https://git.openjdk.java.net/jdk16/pull/6/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk16&pr=6&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8257919
  Stats: 3 lines in 2 files changed: 1 ins; 2 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk16/pull/6.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk16 pull/6/head:pull/6

PR: https://git.openjdk.java.net/jdk16/pull/6