[grokdump] Fix --web instruction output for ARM disassembly

Fixes instruction names to be all in one <td>, rather than being
split between two due to miscalculation of op_offset.

Change-Id: Ieef5d20c238c8e0a5b2316239324d375090006a1
Reviewed-on: https://chromium-review.googlesource.com/777761Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49463}

tools/grokdump.py

@@ -3008,9 +3008,16 @@ class InspectionWebFormatter(object):
     marker = ""
     if stack_slot:
       marker = "=>"
-    op_offset = 3 * num_bytes - 1
 
     code = line[1]
+
+    # Some disassemblers insert spaces between each byte,
+    # while some do not.
+    if code[2] == " ":
+        op_offset = 3 * num_bytes - 1
+    else:
+        op_offset = 2 * num_bytes
+
     # Compute the actual call target which the disassembler is too stupid
     # to figure out (it adds the call offset to the disassembly offset rather
     # than the absolute instruction address).