base: remove execute bit from utf8.cpp, utf8_test.cpp.

Test: none
Change-Id: Idcd7feb2f3a7dc8706c498c55100e82d029858e0
diff --git a/base/utf8.cpp b/base/utf8.cpp
old mode 100755
new mode 100644
diff --git a/base/utf8_test.cpp b/base/utf8_test.cpp
old mode 100755
new mode 100644