tools: require prebuilt command to match exactly with passed arch

If we don't exact match the arch, we can end up accidentially choosing
the wrong binary in tools/record_android_trace

Change-Id: I7c2ea02b2d6895d7fa4e1f6f399339609fa476cd
Fixed: 237662520
diff --git a/tools/trace_processor b/tools/trace_processor
index 48fdc2c..89b7049 100755
--- a/tools/trace_processor
+++ b/tools/trace_processor
@@ -229,9 +229,11 @@
   manifest_entry = None
   for entry in PERFETTO_PREBUILT_MANIFEST:
     # If the caller overrides the arch, just match that (for Android prebuilts).
-    if arch and entry.get('arch') == arch:
-      manifest_entry = entry
-      break
+    if arch:
+      if entry.get('arch') == arch:
+        manifest_entry = entry
+        break
+      continue
     # Otherwise guess the local machine arch.
     if entry.get('tool') == tool_name and entry.get(
         'platform') == plat and machine in entry.get('machine', []):