compiler: fix stack overflow when creating recursive pointer types

There were two types that could result in a compiler stack overflow.
This is difficult to fix in LLVM 14, so I won't even bother. However,
this is trivial to fix with opaque pointers in LLVM 15. Therefore, this
fix is for LLVM 15 only.

Fixes: https://github.com/tinygo-org/tinygo/issues/3341

compiler/testdata/basic.go

@@ -90,3 +90,9 @@ func foo() {
 	// Use this type.
 	func(b kv) {}(kv{})
 }
+
+type T1 []T1
+type T2 [2]*T2
+
+var a T1
+var b T2