[NFC] Fix potential buffer overflow (#5715)

Fixing a clusterfuzz finding.
If the given binary has debug instruction which contained
a badly formatted ANSI escape sequence, the iteration could
go beyond the string length.

Signed-off-by: Nathan Gauër <brioche@google.com>

source/disassemble.cpp

diff --git a/source/disassemble.cpp b/source/disassemble.cpp
index aa20fab..0add260 100644
--- a/source/disassemble.cpp
+++ b/source/disassemble.cpp
@@ -605,7 +605,7 @@
     if (line[i] == '\x1b') {
       do {
         ++i;
-      } while (line[i] != 'm');
+      } while (i < line.size() && line[i] != 'm');
       continue;
     }