v8: fix postmortem and dtrace helper build

Regardless of previous @bnoordhuis' changes

deps/v8/tools/gen-postmortem-metadata.py

@@ -76,6 +76,7 @@ consts_misc = [
     { 'name': 'SmiTag',                 'value': 'kSmiTag' },
     { 'name': 'SmiTagMask',             'value': 'kSmiTagMask' },
     { 'name': 'SmiValueShift',          'value': 'kSmiTagSize' },
+    { 'name': 'SmiShiftSize',           'value': 'kSmiShiftSize' },
     { 'name': 'PointerSizeLog2',        'value': 'kPointerSizeLog2' },
 
     { 'name': 'prop_desc_key',

src/v8abbr.h

@@ -67,7 +67,7 @@
 #define V8_OFF_STR_LENGTH \
     V8_OFF_HEAP(V8DBG_CLASS_STRING__LENGTH__SMI)
 #define V8_OFF_STR_CHARS  \
-    V8_OFF_HEAP(V8DBG_CLASS_SEQONEBYTESTRING__CHARS__CHAR)
+    V8_OFF_HEAP(V8DBG_CLASS_SEQASCIISTRING__CHARS__CHAR)
 #define V8_OFF_CONSSTR_CAR  \
     V8_OFF_HEAP(V8DBG_CLASS_CONSSTRING__FIRST__STRING)
 #define V8_OFF_CONSSTR_CDR  \