RFR: 8316305: Initial buffer size of StackWalker is too small caused by JDK-8285447 [v3]

[Mandy Chung]

> A trivial fix.   [JDK-8285447](https://bugs.openjdk.org/browse/JDK-8285447) intends to change the initial batch size only for a stack walker with an estimated stack depth. For stack walkers without user-supplied estimated stack depth, the initial batch size is changed to 3 which is a bug.  This causes the stack walker to fetch the second batch after walking 2 frames.

Mandy Chung has updated the pull request incrementally with one additional commit since the last revision:

  Revert this change. PR 15876

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15749/files
  - new: https://git.openjdk.org/jdk/pull/15749/files/6cd1d09d..67971b46

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15749&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15749&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/15749.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15749/head:pull/15749

PR: https://git.openjdk.org/jdk/pull/15749