Fix GCC 4.7 warnings, which are related to char being signed in GCC

test/cctest/test-regexp.cc

Index: test/cctest/test-regexp.cc
===================================================================
--- test/cctest/test-regexp.cc	(revision 10237)
+++ test/cctest/test-regexp.cc	(working copy)
@@ -836,7 +836,8 @@
   Handle<Code> code = Handle<Code>::cast(code_object);
 
   int captures[4] = {42, 37, 87, 117};
-  const uc16 input_data[6] = {'f', 'o', 'o', 'f', 'o', '\xa0'};
+  const uc16 input_data[6] = {'f', 'o', 'o', 'f', 'o',
+                              static_cast<uc16>('\xa0')};
   Handle<String> input =
       factory->NewStringFromTwoByte(Vector<const uc16>(input_data, 6));
   Handle<SeqTwoByteString> seq_input = Handle<SeqTwoByteString>::cast(input);
@@ -856,7 +857,8 @@
   CHECK_EQ(-1, captures[2]);
   CHECK_EQ(-1, captures[3]);
 
-  const uc16 input_data2[9] = {'b', 'a', 'r', 'b', 'a', 'r', 'b', 'a', '\xa0'};
+  const uc16 input_data2[9] = {'b', 'a', 'r', 'b', 'a', 'r', 'b', 'a',
+                               static_cast<uc16>('\xa0')};
   input = factory->NewStringFromTwoByte(Vector<const uc16>(input_data2, 9));
   seq_input = Handle<SeqTwoByteString>::cast(input);
   start_adr = seq_input->GetCharsAddress();