Add .clang-format and run clang-format on runtime/platform.

runtime/platform/floating_point.h

Index: runtime/platform/floating_point.h
diff --git a/runtime/platform/floating_point.h b/runtime/platform/floating_point.h
index 24d2f9c17bf1339e084d223ba50ef16ef3408094..0d29a707d01a3bea9a17532d7b122bb3ed9227ff 100644
--- a/runtime/platform/floating_point.h
+++ b/runtime/platform/floating_point.h
@@ -5,7 +5,11 @@
 #ifndef RUNTIME_PLATFORM_FLOATING_POINT_H_
 #define RUNTIME_PLATFORM_FLOATING_POINT_H_
 
-inline double fmod_ieee(double x, double y) { return fmod(x, y); }
-inline double atan2_ieee(double y, double x) { return atan2(y, x); }
+inline double fmod_ieee(double x, double y) {
+  return fmod(x, y);
+}
+inline double atan2_ieee(double y, double x) {
+  return atan2(y, x);
+}
 
 #endif  // RUNTIME_PLATFORM_FLOATING_POINT_H_