[sanitizer] Intercept glibc's argp_parse()

[sanitizer] Intercept glibc's argp_parse()

Glibc provides the argp_parse() function for parsing command line
arguments [1].

Indicate that argc/argv are read from and arg_index is written to.
Strictly speaking, we also need to indicate that argp is read from,
but this would require describing its layout, and most people use a
static initializer there, so it's not worth the effort.

[1] https://www.gnu.org/software/libc/manual/html_node/Argp.html

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D143330