[Bug classpath/90755] BigDecimal.stripTrailingZero throws exception if value is zero

[guillerodriguez.dev at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90755

--- Comment #1 from Guillermo Rodriguez <guillerodriguez.dev at gmail dot com> 
---
Here's a simple fix:

  public BigDecimal stripTrailingZeros()
  {
+   if (intVal.signum() == 0) return ZERO;

    String intValStr = intVal.toString();
    [...]