Add REPORTF test macro.

This macro replaces:
    SkString str;
    str.printf("Foo test Expected %d got %d", x, y);
    reporter->reportFailed(str);
with the shorter code:
    REPORTF(reporter, ("Foo test Expected %d got %d", x, y));

The new form also appends __FILE__:__LINE__ to the message before calling reportFailed().

BUG=
R=mtklein@google.com

Review URL: https://codereview.chromium.org/132843002

git-svn-id: http://skia.googlecode.com/svn/trunk@13016 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/MathTest.cpp b/tests/MathTest.cpp
index 8cba67d..58dd0c6 100644
--- a/tests/MathTest.cpp
+++ b/tests/MathTest.cpp
@@ -225,10 +225,8 @@
 static void assert_float_equal(skiatest::Reporter* reporter, const char op[],
                                float x, uint32_t ni, uint32_t si) {
     if (!equal_float_native_skia(x, ni, si)) {
-        SkString desc;
-        uint32_t xi = SkFloat2Bits(x);
-        desc.printf("%s float %g bits %x native %x skia %x\n", op, x, xi, ni, si);
-        reporter->reportFailed(desc);
+        ERRORF(reporter, "%s float %g bits %x native %x skia %x\n",
+               op, x, SkFloat2Bits(x), ni, si);
     }
 }