Add regression test for inheritance crash

Amp-Thread-ID: https://ampcode.com/threads/T-3ff237da-1bb4-43d1-abb5-989b228d9f59

Author: jupblb

test/scip/testdata/inheritance_crash.rb

@@ -0,0 +1,10 @@
+# typed: false
+
+# This reproduces a crash where a class inherits from a constant.
+# The constant symbol is a static field, not a class/module.
+# scip-ruby used to crash when trying to cast this symbol to a ClassOrModuleRef.
+
+Base = Object
+
+class Child < Base
+end

test/scip/testdata/inheritance_crash.snapshot.rb

@@ -0,0 +1,15 @@
+ # typed: false
+ 
+ # This reproduces a crash where a class inherits from a constant.
+ # The constant symbol is a static field, not a class/module.
+ # scip-ruby used to crash when trying to cast this symbol to a ClassOrModuleRef.
+ 
+ Base = Object
+#^^^^ definition [..] Base.
+#relation reference=[..] Object#
+#^^^^^^^^^^^^^ reference [..] Base.
+#       ^^^^^^ reference [..] Object#
+ 
+ class Child < Base
+#      ^^^^^ definition [..] Child#
+ end