Merge the latest bug fixes between 11+28 and 11.0.13-ga

11+28 is a pre-release version, and we haven't released this
version on Android. So we should upgrade them to the version
11.0.13-ga before an Android release.

Some example bug fixes:
1. some arithmetic API bug fixes in Math / BigInteger / BigDecimal
2. Performance improvement in  BufferedReader

Bug: 226374336
Test: atest CtsLibcoreOjTestCases
Test: atest CtsLibcoreTestCases
Change-Id: Ifaa9bfe2b9c78a5b44a3cbeab60b0c435aeefe82