Use an std::vector for inline_states

Use an std::vector for inline_states

This patch replaces VEC(inline_state) with std::vector<inline_state> and
adjusts the code that uses it.

gdb/ChangeLog:

	* common/gdb_vecs.h (unordered_remove): Add overload that takes
	an iterator.
	* inline-frame.c: Include <algorithm>.
	(struct inline_state): Add constructor.
	(inline_state_s): Remove.
	(DEF_VEC_O(inline_state_s)): Remove.
	(inline_states): Change type to std::vector.
	(find_inline_frame_state): Adjust to std::vector.
	(allocate_inline_frame_state): Remove.
	(clear_inline_frame_state): Adjust to std::vector.
	(skip_inline_frames): Adjust to std::vector.