fixed safe but illegal out-of-bounds std::vector accesses that cause VS builds to break in debug when using OSL.

Author: dictoon

src/osl/src/liboslexec/oslexec_pvt.h

@@ -521,14 +521,14 @@ class ShaderInstance {
             return std::pair<Symbol*,Symbol*> ((Symbol*)NULL, (Symbol*)NULL);
         else
             return std::pair<Symbol*,Symbol*> (&i->m_instsymbols[0],
-                                               &i->m_instsymbols[i->m_instsymbols.size()]);
+                                               &i->m_instsymbols[0] + i->m_instsymbols.size());
     }
     friend std::pair<const Symbol *,const Symbol *> sym_range (const ShaderInstance *i) {
         if (i->m_instsymbols.size() == 0)
             return std::pair<const Symbol*,const Symbol*> ((const Symbol*)NULL, (const Symbol*)NULL);
         else
             return std::pair<const Symbol*,const Symbol*> (&i->m_instsymbols[0],
-                                               &i->m_instsymbols[i->m_instsymbols.size()]);
+                                                           &i->m_instsymbols[0] + i->m_instsymbols.size());
     }
 
     int Psym () const { return m_Psym; }