Fixed bound on memcpy loop in thumb,arm,aarch64

Author: themaks

pwnlib/shellcraft/templates/aarch64/memcpy.asm

@@ -16,4 +16,4 @@ ${memcpy_loop}:
     ldrb w3, [x1], #1
     strb w3, [x0], #1
     subs x2, x2, #1
-    bge ${memcpy_loop}
+    bgt ${memcpy_loop}

pwnlib/shellcraft/templates/arm/memcpy.asm

@@ -16,4 +16,4 @@ ${memcpy_loop}:
     ldrb r3, [r1], #1
     strb r3, [r0], #1
     subs r2, r2, #1
-    bge ${memcpy_loop}
+    bgt ${memcpy_loop}

pwnlib/shellcraft/templates/thumb/memcpy.asm

@@ -16,4 +16,4 @@ ${memcpy_loop}:
     ldrb r3, [r1], #1
     strb r3, [r4], #1
     subs r2, r2, #1
-    bge ${memcpy_loop}
+    bgt ${memcpy_loop}