opline: move cop_line to BASEOP

Looking up COP's to find the error lines is inexact, slow and esp.
8% heavier than using less COP's and moving the opline to each op.

On an average of 4 ops per line, and the reduced need for
runtime nextstates of 90% - only lexstate changes and file beginning
and the overhead of 5 ptrs per COP, we will win 4ptrs per reduced COP.
On typical 10k src with 40k ops it will be a 4 ptrs(5-1)*10k memory win: 40kb
(4 ops per line on average), plus the runtime win of ~about 4k ops, 8%.

See [cperl #333]

cop.h

@@ -393,9 +393,6 @@ string/length pair.
 
 struct cop {
     BASEOP
-    /* On LP64 putting this here takes advantage of the fact that BASEOP isn't
-       an exact multiple of 8 bytes to save structure padding.  */
-    line_t      cop_line;       /* line # of this command */
     /* label for this construct is now stored in cop_hints_hash */
 #ifdef USE_ITHREADS
     PADOFFSET	cop_stashoff;	/* offset into PL_stashpad, for the
@@ -547,7 +544,7 @@ be zero.
 #define CopLABEL_alloc(pv)	((pv)?savepv(pv):NULL)
 
 #define CopSTASH_ne(c,hv)	(!CopSTASH_eq(c,hv))
-#define CopLINE(c)		((c)->cop_line)
+#define CopLINE(c)		((c)->op_line)
 #define CopLINE_inc(c)		(++CopLINE(c))
 #define CopLINE_dec(c)		(--CopLINE(c))
 #define CopLINE_set(c,l)	(CopLINE(c) = (l))

op.h

@@ -66,7 +66,8 @@ typedef PERL_BITFIELD16 Optype;
     PERL_BITFIELD16 op_typechecked:1;	\
     U8		op_flags;		\
     U8		op_private;             \
-    U8		op_rettype;
+    U8		op_rettype;             \
+    line_t      op_line;       /* line # of this command */
 #endif
 
 /* Class::XSAccessor abuses this */