fix windows compile errors in "tests"



git-svn-id: http://skia.googlecode.com/svn/trunk@1547 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/MathTest.cpp b/tests/MathTest.cpp
index 7a9364f..efdad3a 100644
--- a/tests/MathTest.cpp
+++ b/tests/MathTest.cpp
@@ -188,7 +188,7 @@
 
 static void unittest_isfinite(skiatest::Reporter* reporter) {
 #ifdef SK_SCALAR_IS_FLOAT
-    float nan = ::asin(2);
+    float nan = sk_float_asin(2);
     float inf = 1.0 / make_zero();
     float big = 3.40282e+038;