Add API to check certificate chain signatures

Add hidden API to check certificate chain signatures when needed. The
getCertificates implementation returns a list of all the certificates and
chains and would expect any caller interested in verifying actual chains
to call getCodeSigners instead.

We add this hidden constructor as a stop-gap until we can switch callers
over to getCodeSigners.

Bug: 13678484
Change-Id: I01cddef287767422454de4c5fd266c812a04d570
Implements some math functions for faster performance

Changes cosh, exp, expm1, log, log10, sinh, cbrt,
asin, acos, atan, tanh, log1p
These functions are now implemnted in java to
save the overhead of a jni call

Change-Id: I4d3b70dd1693378af5b04cbbe0fecd95d97c1cff