Avoid wrong memory access due to double substitution and %%

Use the form SkDebugf("%s", arbitraryString) instead of
SkDebugf(arbitraryString).

Fixes the case where SkString::appendf-ing a string with "%%" and then
printing the string with SkDebugf would cause uninitialized read and
corrupted debug print.

ninja -C out/Debug tools && valgrind --leak-check=full
./out/Debug/render_pictures --config gpu  -w q -r ...

...

==7307== Conditional jump or move depends on uninitialised value(s)
==7307==    at 0x6908475: __printf_fp (printf_fp.c:1180)
==7307==    by 0x6904267: vfprintf (vfprintf.c:1629)
==7307==    by 0x6906E53: buffered_vfprintf (vfprintf.c:2313)
==7307==    by 0x690188D: vfprintf (vfprintf.c:1316)
==7307==    by 0x67E8F5: SkDebugf(char const*, ...) (SkDebug_stdio.cpp:18)
==7307==    by 0x7983F1: GrContext::printCacheStats() const (GrTest.cpp:54)
==7307==    by 0x408ECF: tool_main(int, char**) (render_pictures_main.cpp:480)
==7307==    by 0x40913E: main (render_pictures_main.cpp:511)
==7307==
Budget: 2048 items 100663296 bytes
		Entry Count: current 652 (651 budgeted, 0 wrapped, 297 locked, 638 scratch 32 0.000000ull), high 652
		Entry Bytes: current 51087658 (budgeted 49826658, 49 0.000000ull, 1261000 unbudgeted) high 51087658

(observe "ull" instead of "% full")

(from mtklein)
This CL is not editing public API.
TBR=reed@google.com

Review URL: https://codereview.chromium.org/943453002
9 files changed