class_docstr: Filtering out a function should be identical to never adding it
  
  This test is to guard against hidden state in the IRModule that
  remains after filtering.  Previously, this was observed in the
  `IRModuleNode::global_var_map_`, which retained entries of
  filtered-out functions.
code: def before(self):
      @I.ir_module
      class module:
          @T.prim_func
          def func():
              T.evaluate(0)
  
      return module
  
imports: import pytest
  import tvm
  from tvm.script import tir, ir
  import tvm.testing
label_desc: Use image node_id 1 for calling the TestFilterRemovesGlobalVarMap obj's underlying member method code with example usage: obj.before() and returns: module