Fix breakpoint thread condition missing with mi and a pending breakpoint.

Fix breakpoint thread condition missing with mi and a pending breakpoint.

When setting a pending breakpoint with a thread condition while using
the mi interface, the thread condition would be lost by gdb when the breakpoint
was resolved.

This patch fixes this behavior by setting the thread condition properly in the
mi case.

Also, this patch modifies the mi-pending test case to test for this issue and
removes some unneeded code in the testcase and dependency on stdio.

gdb/Changelog:
	PR breakpoints/16466
	* breakpoint.c (create_breakpoint): Set thread on breakpoint struct.

gdb/testsuite/ChangeLog:
	PR breakpoints/16466
	* gdb.mi/Makefile.in: Add mi-pendshr2.sl to cleanup.
	* gdb.mi/mi-pending.c (thread_func): New function.
	(int main): Add threading support required.
	* gdb.mi/mi-pending.exp: Add tests for this issue.
	* gdb.mi/mi-pendshr.c (pendfunc1): Remove stdio dependency.
	(pendfunc2): Remove stdio dependency.
	* gdb.mi/mi-pendshr2.c: New file.