This removes the long_long_align_bit gdbarch attribute in favor of
type_align.  This uncovered two possible issues.

First, arc-tdep.c claimed that long long alignment was 32 bits, but as
discussed on the list, ARC has a maximum alignment of 32 bits, so I've
added an arc_type_align function to account for this.

Second, jit.c, the sole user of long_long_align_bit, was confusing
"long long" with uint64_t.  The relevant structure is defined in the
JIT API part of the manual as:

     struct jit_code_entry
     {
       struct jit_code_entry *next_entry;
       struct jit_code_entry *prev_entry;
       const char *symfile_addr;
       uint64_t symfile_size;
     };

I've changed this code to use uint64_t.

2018-04-30  Tom Tromey  <tom@tromey.com>

	* jit.c (jit_read_code_entry): Use type_align.
	* i386-tdep.c (i386_gdbarch_init): Don't call
	set_gdbarch_long_long_align_bit.
	* gdbarch.sh: Remove long_long_align_bit.
	* gdbarch.c, gdbarch.h: Rebuild.
	* arc-tdep.c (arc_type_align): New function.
	(arc_gdbarch_init): Use arc_type_align.  Don't call
	set_gdbarch_long_long_align_bit.