x86: Avoid abort on invalid broadcast

Print "{bad}" on invalid broadcast instead of abort.

gas/

	PR binutils/28247
	* testsuite/gas/i386/bad-bcast.d: New file.
	* testsuite/gas/i386/bad-bcast.s: Likewise.
	* testsuite/gas/i386/i386.exp: Run bad-bcast.

opcodes/

	PR binutils/28247
	* i386-dis.c (OP_E_memory): Print "{bad}" on invalid broadcast
	instead of abort.

gas/testsuite/gas/i386/bad-bcast.d

@@ -0,0 +1,14 @@
+#objdump: -dw
+#name: Disassemble bad broadcast
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+0+ <.text>:
+ +[a-f0-9]+:	62                   	.byte 0x62
+ +[a-f0-9]+:	c3                   	ret    
+ +[a-f0-9]+:	8c 1d 66 90 66 90    	mov    %ds,0x90669066
+ +[a-f0-9]+:	66 90                	xchg   %ax,%ax
+#pass

gas/testsuite/gas/i386/bad-bcast.s

@@ -0,0 +1,2 @@
+	.text
+	.byte 0x62, 0xc3, 0x8c, 0x1d, 0x66, 0x90, 0x66, 0x90, 0x66, 0x90

gas/testsuite/gas/i386/i386.exp

@@ -646,6 +646,7 @@ if [gas_32_check] then {
 	run_dump_test "dw2-compress-2"
 	run_dump_test "dw2-compressed-2"
 
+	run_dump_test "bad-bcast"
 	run_dump_test "bad-size"
 
 	run_dump_test "size-1"

opcodes/i386-dis.c

@@ -11912,7 +11912,7 @@ OP_E_memory (int bytemode, int sizeflag)
         {
           if (vex.w)
             {
-              abort ();
+	      oappend ("{bad}");
             }
           else
             {
@@ -11928,7 +11928,7 @@ OP_E_memory (int bytemode, int sizeflag)
                   oappend ("{1to32}");
                   break;
                 default:
-                  abort ();
+		  oappend ("{bad}");
                 }
             }
         }
@@ -11948,7 +11948,7 @@ OP_E_memory (int bytemode, int sizeflag)
 	      oappend ("{1to8}");
 	      break;
 	    default:
-	      abort ();
+	      oappend ("{bad}");
 	    }
 	}
       else if (bytemode == x_mode
@@ -11966,7 +11966,7 @@ OP_E_memory (int bytemode, int sizeflag)
 	      oappend ("{1to16}");
 	      break;
 	    default:
-	      abort ();
+	      oappend ("{bad}");
 	    }
 	}
       else