gcc 10.2.1 produces an uninitialized warning in sharedRuntimeTrig.cpp

Opening on behalf of Joshua Cao <joshcao@amazon.com>

There is a warning when trying to build OpenJDK11 using gcc10.2.1. This warning does not happen when building newer JDK versions, it seems JDK-8211029 disabled the warning for maybe-uninitialized.

* For target hotspot_variant-server_libjvm_objs_sharedRuntimeTrig.o:
/home/joshcao/jdk/jdk11u-dev/src/hotspot/share/runtime/sharedRuntimeTrig.cpp: In function 'int __kernel_rem_pio2(double*, double*, int, int, int, const int*)':
/home/joshcao/jdk/jdk11u-dev/src/hotspot/share/runtime/sharedRuntimeTrig.cpp:300:14: error: 'fq[0]' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  300 | fw = fq[0]-fw;
      | ~~~~^
cc1plus: all warnings being treated as errors