RFR: 8271003: hs_err improvement: handle CLASSPATH env setting longer than O_BUFLEN [v2]

[Calvin Cheung]

> Please review this small enhancement for addressing the problem of the CLASSPATH env variable setting being truncated in a hs err log.
> 
> For printing a char string, it doesn't need to go through `do_vsnprintf()` which does the truncation based on the input buffer length. The change is local to the code path pertaining to hs err log.
> 
> Testing:
> 
> - [x] tiers 1, 2 (including the new test)

Calvin Cheung has updated the pull request incrementally with one additional commit since the last revision:

  @tstuefe comments

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4947/files
  - new: https://git.openjdk.java.net/jdk/pull/4947/files/0ed841c7..35eccdc6

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4947&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4947&range=00-01

  Stats: 79 lines in 4 files changed: 2 ins; 61 del; 16 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4947.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4947/head:pull/4947

PR: https://git.openjdk.java.net/jdk/pull/4947