[5.3] IRGen: Fix alignment of global variable buffer for non-fixed types

It needs to have the getFixedBufferAlignment because that is the value
we use to determine whether the type will be stored inline in the buffer
or outline in an allocated buffer

rdar://62443743

Author: aschwaighofer

lib/IRGen/GenDecl.cpp

@@ -2224,7 +2224,7 @@ Address IRGenModule::getAddrOfSILGlobalVariable(SILGlobalVariable *var,
     inFixedBuffer = true;
     storageType = getFixedBufferTy();
     fixedSize = Size(DataLayout.getTypeAllocSize(storageType));
-    fixedAlignment = Alignment(DataLayout.getABITypeAlignment(storageType));
+    fixedAlignment = getFixedBufferAlignment(*this);
   }
 
   // Check whether we've created the global variable already.

test/IRGen/global_resilience.sil

@@ -22,7 +22,7 @@ public struct SmallResilientStruct {
   let x: Int32 = 0
 }
 
-// CHECK: @smallGlobal = {{(dllexport )?}}{{(protected )?}}global [[BUFFER:\[(12|24) x i8\]]] zeroinitializer
+// CHECK: @smallGlobal = {{(dllexport )?}}{{(protected )?}}global [[BUFFER:\[(12|24) x i8\]]] zeroinitializer{{.*}}align {{(8|4)}}
 sil_global [let] @smallGlobal : $SmallResilientStruct
 
 //
@@ -77,7 +77,7 @@ bb0:
 sil @testLargeGlobal : $@convention(thin) () -> () {
 bb0:
   // CHECK: [[ALLOC:%.*]] = call noalias i8* @swift_slowAlloc([[INT]] 32, [[INT]] 7)
-  // CHECK: store i8* [[ALLOC]], i8** bitcast ([[BUFFER]]* @largeGlobal to i8**), align 1
+  // CHECK: store i8* [[ALLOC]], i8** bitcast ([[BUFFER]]* @largeGlobal to i8**), align {{(8|4)}}
   alloc_global @largeGlobal
 
   // CHECK: [[VALUE:%.*]] = load %T17global_resilience20LargeResilientStructV*, %T17global_resilience20LargeResilientStructV** bitcast ([[BUFFER]]* @largeGlobal to %T17global_resilience20LargeResilientStructV**)