interp: keep reverted package initializers in order

Previously, a package initializer that could not be reverted correctly
would be called at runtime. But the initializer would be called in the
wrong order: after later packages are initialized.

This commit fixes this oversight and adds a test to verify the new
behavior.

interp/testdata/revert.ll

@@ -0,0 +1,21 @@
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64--linux"
+
+declare void @externalCall(i64)
+
+define void @runtime.initAll() unnamed_addr {
+entry:
+  call void @foo.init(i8* undef, i8* undef)
+  call void @main.init(i8* undef, i8* undef)
+  ret void
+}
+
+define internal void @foo.init(i8* %context, i8* %parentHandle) unnamed_addr {
+  unreachable ; this triggers a revert of @foo.init.
+}
+
+define internal void @main.init(i8* %context, i8* %parentHandle) unnamed_addr {
+entry:
+  call void @externalCall(i64 3)
+  ret void
+}