RFR: 8233760: Result of BigDecimal.toString throws overflow exception on new BigDecimal(str)

[Raffaello Giulietti]

BigDecimal(String) currently fails to accept some strings produced by BigDecimal.toString(). This PR removes this limitation.

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Commit messages:
 - 8233760: Result of BigDecimal.toString throws overflow exception on new BigDecimal(str)

Changes: https://git.openjdk.java.net/jdk/pull/8905/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8905&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8233760
  Stats: 48 lines in 2 files changed: 2 ins; 26 del; 20 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8905.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8905/head:pull/8905

PR: https://git.openjdk.java.net/jdk/pull/8905