Provide "freeBuffer()" primitive for testing under ASan.

src/flag-definitions.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 389 matching lines @@
 DEFINE_bool(enable_unaligned_accesses, true,
             "enable unaligned accesses for ARMv7 (ARM only)")
 DEFINE_bool(enable_32dregs, ENABLE_32DREGS_DEFAULT,
             "enable use of d16-d31 registers on ARM - this requires VFP3")
 DEFINE_bool(enable_vldr_imm, false,
             "enable use of constant pools for double immediate (ARM only)")
 
 // bootstrapper.cc
 DEFINE_string(expose_natives_as, NULL, "expose natives in global object")
 DEFINE_string(expose_debug_as, NULL, "expose debug in global object")
+#ifdef ADDRESS_SANITIZER
+DEFINE_bool(expose_free_buffer, false, "expose freeBuffer extension")
+#endif
 DEFINE_bool(expose_gc, false, "expose gc extension")
 DEFINE_string(expose_gc_as, NULL,
               "expose gc extension under the specified name")
 DEFINE_implication(expose_gc_as, expose_gc)
 DEFINE_bool(expose_externalize_string, false,
             "expose externalize string extension")
 DEFINE_int(stack_trace_limit, 10, "number of stack frames to capture")
 DEFINE_bool(builtins_in_stack_traces, false,
             "show built-in functions in stack traces")
 DEFINE_bool(disable_native_files, false, "disable builtin natives files")
@@ skipping 470 matching lines @@
 #undef DEFINE_ALIAS_float
 #undef DEFINE_ALIAS_args
 
 #undef FLAG_MODE_DECLARE
 #undef FLAG_MODE_DEFINE
 #undef FLAG_MODE_DEFINE_DEFAULTS
 #undef FLAG_MODE_META
 #undef FLAG_MODE_DEFINE_IMPLICATIONS
 
 #undef COMMA