Fixed an issue where a lexical block or inlined function might have bad debug

information generated for it. Say we have a concrete function "foo" which
has inlined function "a" which calls another inlined function "b":

    foo
1   {
2       {
            a ()
3           {
                b ()
4               {
                
                }
            }
        }
    }
    
Sometimes we see the compiler generate an address range in the DWARF for "foo"
(block 1 above) as say [0x1000-0x1100). Then the range for "a" is something
like [0x1050-0x1060) (note that it is correctly scoped within the "foo" 
address range). And then we get "b" which is a child of "a", yet the debug
info says it has a range of [0x1060-0x1080) (not contained within "a"). We now
detect this issue when making our blocks and add an extra range to "a".

Also added a new "lldb" logging category named "symbol" where we can find out
about symbol file errors and warnings.

llvm-svn: 140822