Eliminate PointerType::getContainedType() calls

LLVM is removing pointee type information from pointers:
https://llvm.org/docs/OpaquePointers.html. This means getContainedType()
is slated to be removed.

Reactor only used it in asserts to make sure the type matches what
LLVM expects, to avoid asserts in LLVM itself. Since the latter are
removed, we no longer need the asserts in Reactor either. Note our type
system for Pointer<T> already prevented mistakes in its semantic usage.

Bug: b/165000222
Bug: b/179837109
Change-Id: If8ec095e67b8e6176aa87e20822ac325095b8ece
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/65828
Reviewed-by: Alexis Hétu <sugoi@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Arthur Eubanks <aeubanks@google.com>
diff --git a/src/Reactor/LLVMReactor.cpp b/src/Reactor/LLVMReactor.cpp
index cb41563..f353a26 100644
--- a/src/Reactor/LLVMReactor.cpp
+++ b/src/Reactor/LLVMReactor.cpp
@@ -878,7 +878,6 @@
 	case Type_LLVM:
 		{
 			auto elTy = T(type);
-			ASSERT(V(ptr)->getType()->getContainedType(0) == elTy);
 
 			if(!atomic)
 			{
@@ -962,7 +961,6 @@
 	case Type_LLVM:
 		{
 			auto elTy = T(type);
-			ASSERT(V(ptr)->getType()->getContainedType(0) == elTy);
 
 			if(__has_feature(memory_sanitizer) && !jit->msanInstrumentation)
 			{
@@ -1238,7 +1236,7 @@
 Value *Nucleus::createGEP(Value *ptr, Type *type, Value *index, bool unsignedIndex)
 {
 	RR_DEBUG_INFO_UPDATE_LOC();
-	ASSERT(V(ptr)->getType()->getContainedType(0) == T(type));
+
 	if(sizeof(void *) == 8)
 	{
 		// LLVM manual: "When indexing into an array, pointer or vector,