Fix Double.toString() for a tie case

The double with bit pattern 0x406E533340000000L falls between
decimal values 242.60000610351562 and 242.60000610351563. i.e.
parsing either value will result in that double bit pattern.
The tie between the two is close and Android is not picking the
"correct" value. The Steele/White paper "How to Print
Floating-Point Numbers Accurately" algorithm (Table 3) suggests
the algorithm in RealToString should be picking the lower, not
the higher.

Bug: 24195419
Change-Id: Id67ed68939b30e0e1698dce94a56d530c5a4b04b
2 files changed