[NFC][update_llc_test_checks] Remove the redundant SCRUB_LOOP_COMMENT_RE in asm.py

Summary:
In the patch: https://reviews.llvm.org/D42654
De-duplicate utils/update_{llc_,}test_checks.py, Some common part has
been move to common.py. The SCRUB_LOOP_COMMENT_RE has been moved to
common.py, but forgetting to remove from asm.py.
This patch is to remove the redundant SCRUB_LOOP_COMMENT_RE in asm.py
and use common.SCRUB_LOOP_COMMENT_RE.
diff --git a/llvm/utils/UpdateTestChecks/asm.py b/llvm/utils/UpdateTestChecks/asm.py
index ea416ed..68f826e 100644
--- a/llvm/utils/UpdateTestChecks/asm.py
+++ b/llvm/utils/UpdateTestChecks/asm.py
@@ -140,10 +140,6 @@
     r'^\s*(\.Lfunc_end[0-9]+:\n|end_function)',
     flags=(re.M | re.S))
 
-
-SCRUB_LOOP_COMMENT_RE = re.compile(
-    r'# =>This Inner Loop Header:.*|# in Loop:.*', flags=re.M)
-
 SCRUB_X86_SHUFFLES_RE = (
     re.compile(
         r'^(\s*\w+) [^#\n]+#+ ((?:[xyz]mm\d+|mem)( \{%k\d+\}( \{z\})?)? = .*)$',
@@ -234,7 +230,7 @@
   # Expand the tabs used for indentation.
   asm = string.expandtabs(asm, 2)
   # Stripe unimportant comments, but leave the token '#' in place.
-  asm = SCRUB_LOOP_COMMENT_RE.sub(r'#', asm)
+  asm = common.SCRUB_LOOP_COMMENT_RE.sub(r'#', asm)
   # Strip trailing whitespace.
   asm = common.SCRUB_TRAILING_WHITESPACE_RE.sub(r'', asm)
   return asm