llvm-dwarfdump: Add new variable, parameter and inlining statistics; …

…also function source location statistics.

Add statistics for abstract origins, function, variable and parameter
locations; break the 'variable' counts down into variables and
parameters. Also update call site counting to check for
DW_AT_call_{file,line} in addition to DW_TAG_call_site.

Differential revision: https://reviews.llvm.org/D58849

llvm-svn: 355243