Optimizer: support static initialization of global arrays

The buffer of global arrays could already be statically initialized.
The missing piece was the array itself, which is basically a reference to the array buffer.
For example:
```
var a = [1, 2, 3]
```
ends up in two statically initialized globals:
1. the array buffer, which contains the elements
2. the variable `a` which is a single reference (= pointer) of the array buffer

This optimization removes the need for lazy initialization of such variables.

rdar://127757554

SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyLoad.swift

@@ -250,7 +250,7 @@ private func getInitializerFromInitFunction(of globalAddr: GlobalAddrInst, _ con
   }
   let initFn = initFnRef.referencedFunction
   context.notifyDependency(onBodyOf: initFn)
-  guard let (_, storeToGlobal) = getGlobalInitialization(of: initFn, allowGlobalValue: true)  else {
+  guard let (_, storeToGlobal) = getGlobalInitialization(of: initFn, forStaticInitializer: false, context) else {
     return nil
   }
   return storeToGlobal.source