math: Use precomputed constant for log2(10.0)

exp10 CTS fails with or without this change

Reviewer: Jeroen Ketema
Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>
llvm-svn: 318063
GitOrigin-RevId: 79b7566210fde40f70bdf4b2e8f914ca0680657c
3 files changed