[AArch64][GISel] Expand coverage of FRem.

This adds some more extensive test coverage for frem through global isel,
making sure that vector types are all scalarized and all fp16 become f32
libcalls.

Author: davemgreen

llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp

@@ -252,7 +252,10 @@ AArch64LegalizerInfo::AArch64LegalizerInfo(const AArch64Subtarget &ST)
       .clampNumElements(0, v2s64, v2s64)
       .moreElementsToNextPow2(0);
 
-  getActionDefinitionsBuilder(G_FREM).libcallFor({s32, s64});
+  getActionDefinitionsBuilder(G_FREM)
+      .libcallFor({s32, s64})
+      .minScalar(0, s32)
+      .scalarize(0);
 
   getActionDefinitionsBuilder({G_FMA, G_INTRINSIC_LRINT})
       // If we don't have full FP16 support, then scalarize the elements of