chore: remove entire VM test suite and update test README for CLI-only focus

Delete all VM-related test files including benchmark, call, error, foreign_class, and other API tests, along with their C source, headers, and Wren scripts. Rewrite test/README.md to describe only CLI unit tests and module resolution tests, removing references to VM, compiler, core library, and language semantics tests.

test/module/logical_short/logical_short.wren

@@ -0,0 +1,5 @@
+// Import a module whose name is the same as the package.
+import "foo" for Module
+// expect: ran module
+
+System.print(Module) // expect: from module

test/module/logical_short/wren_modules/foo/foo.wren

@@ -0,0 +1,3 @@
+// nontest
+var Module = "from module"
+System.print("ran module")