26_numerics/complex/13450.cc and IBM long double

[Gabriel Dos Reis]

"Joseph S. Myers" <joseph@codesourcery.com> writes:

| The libstdc++ test 26_numerics/complex/13450.cc cannot work reliably for 
| IBM long double, since we define epsilon correctly for this type which 
| means 100 * epsilon can be smaller than 1ulp for a particular long double 
| value (and so the test is only likely to pass if all three computed 
| complex values are actually identical).  Thus this patch disables the long 
| double testing in this testcase for the IBM long double case.  OK to 
| commit?

OK.