Fix parsing of zero with a large exponent (PR#15976)

git-svn-id: https://svn.r-project.org/R/trunk@66939 00db46b3-68df-0310-9c12-caf00c1e9a41
Tweak display in line profiling, so Windows paths are displayed correctly.

git-svn-id: https://svn.r-project.org/R/trunk@66941 00db46b3-68df-0310-9c12-caf00c1e9a41