Introduce arch-specific checker tests.

- The '.cfg' output is now created on target.
- Arch-specific checker tests can be created by inserting a
  suffix. For example:
      /// CHECK-START-ARM64: int Main.foo(int) register (after)
      /// CHECK-DAG:   <<Arg:i\d+>>     ParameterValue

Change-Id: I55cdb37f8e806c7ffdde6b676c8f44ac30b59051
diff --git a/tools/checker/match/file.py b/tools/checker/match/file.py
index b22211a..42ca7df 100644
--- a/tools/checker/match/file.py
+++ b/tools/checker/match/file.py
@@ -150,8 +150,10 @@
     matchFrom = match.scope.end + 1
     variables = match.variables
 
-def MatchFiles(checkerFile, c1File):
+def MatchFiles(checkerFile, c1File, targetArch):
   for testCase in checkerFile.testCases:
+    if testCase.testArch not in [None, targetArch]:
+      continue
     # TODO: Currently does not handle multiple occurrences of the same group
     # name, e.g. when a pass is run multiple times. It will always try to
     # match a check group against the first output group of the same name.