implemented DecimalFormat using icu4j

The change fixes test_formatDouble_scientificNotation,
test_formatDouble_scientificNotationMinusZero,
test_formatDouble_withFieldPosition, test_formatLong_scientificNotation,
test_parse_withMultiplier.

Tests - testSerializationHarmonyRICompatible,
test_formatDouble_withFieldPosition,
test_formatToCharacterIterator_original are to be fixed.

Also, unused variables and methods has been removed.

Bug: 26022696
Bug: 26024115
Bug: 25993727
Bug: 25860873

Change-Id: I867d1366bfac0f3f94c0184275868f78609d2303
2 files changed