Add handling of trailing zeroes in numeric parser

:Release Notes:
Fix tests parse_unbalanced_big, parse_mantissa_overflow and
parse_decimal_overflow_by_mantissa from NumberTest (gtest_mojocore)

:Detailed Notes:
- Postpone processing of trailing zeroes to be able to re-aling with
  exponent. That fixes NumberTest.parse_unbalanced_big.
- Increase mantissa used for checking overflow since MojDecimal since
  in comparison with MojDecimal this parser can handle more digits.
- Add parse_mantissa_bound and parse_mantissa_overflow_bound to ensure
  correct behavior on boundary of possible values.

:Testing Performed:
test_core and gtest_mojocore on desktop build

:QA Notes:

:Issues Addressed:
[GF-36958] MojDecimal in DB8 have issues with rounding and exponent

Open-webOS-DCO-1.0-Signed-off-by: Nikolay Orliuk <nikolay.orliuk@lge.com>

Change-Id: I1064b626137c4eeba4cb59acf419bb39ac2d8f42
Reviewed-on: https://g2g.palm.com/3322
Reviewed-by: Build Verification
Reviewed-by: Roger Stringer <roger.stringer@lge.com>
Tested-by: Roger Stringer <roger.stringer@lge.com>