Fix exception when doing expect boolean = ..

Add new Air Assert Bool
Add acceptance test 76

examples/acceptance_tests/076/aiken.lock

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+# This file was generated by Aiken
+# You typically do not need to edit this file
+
+requirements = []
+packages = []

examples/acceptance_tests/076/aiken.toml

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+name = 'aiken-lang/acceptance_test_076'
+version = '0.0.0'
+description = ''

examples/acceptance_tests/076/lib/tests.ak

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+test expect_positive() {
+  let val = 5
+  expect True = val > 0
+  True
+}