[analyzer] Relax constraints on const qualified regions

[steakhal]

Summary

The arithmetic restriction seems to be artificial.
The comment below seems to be stale.
Thus, we remove both.

Depends on D127306.

[martong]

LGTM.

[steakhal]

According to my measurements, this change has minor effects (1 new, 20 disappeared reports).
The interesting reports had really long bug paths, so I think there were some default eval called functions down the line which made this patch surface this way.

clang/lib/StaticAnalyzer/Core/MemRegion.cpp

const VarRegion *MemRegionManager::getVarRegion(const VarDecl *D,
   }
 
   D = D->getCanonicalDecl();
   const MemRegion *sReg = nullptr;
 
   if (D->hasGlobalStorage() && !D->isStaticLocal()) {
     QualType Ty = D->getType();
     assert(!Ty.isNull());
-    if (Ty.isConstQualified() && Ty->isArithmeticType()) {
-      // TODO: We could walk the complex types here and see if everything is
-      // constified.
+    if (Ty.isConstQualified()) {
       sReg = getGlobalsRegion(MemRegion::GlobalImmutableSpaceRegionKind);
     } else if (Ctx.getSourceManager().isInSystemHeader(D->getLocation())) {
       sReg = getGlobalsRegion(MemRegion::GlobalSystemSpaceRegionKind);
     } else {
       sReg = getGlobalsRegion(MemRegion::GlobalInternalSpaceRegionKind);
     }
 
   // Finally handle static locals.