dbghelp: Don't include global & static variables from S_LOCAL* records.

dbghelp: Don't include global & static variables from S_LOCAL* records.

PDB supports description of a global or static variable:
- accessed from a register
- stored as a local variable record inside a function

This likely describes access to a global/static variable where
intermediate computation is kept in a register.

We cannot store this kind of entries in local variable lists
(builtin dbghelp and winedbg are not prepared to handle a global variable)

Note: the global or static Codeview data record is still present (with a
relocatable address), so the variable should still be available from global
access (but could be not up-to-date if temporarly stored in a register).

Signed-off-by: Eric Pouech <eric.pouech@gmail.com>