Utils.cpp: IWYU fix for FLT_MAX

Utils.cpp uses FLT_MAX which is defined in float.h. Based on the
include-what-you-use principle, float.h should be directly rather than
indirectly included.

Also removes the system_properties.h include, as nothing directly
defined in that file is used in Utils.cpp.

This explicit inclusion is necessary to allow compilation on ChromiumOS.

Test: Still compiles

Change-Id: I9ac457ef85eb3cb98fab418e6e5c35bcea38b155
1 file changed