fix parser and tests

[rsoeldner]

pactTests
  Core repl tests
    base64.repl:      OK
    lists.repl:       OK
    strings.repl:     OK
    ops.repl:         FAIL
      Exception: unimplemented
      CallStack (from HasCallStack):
        error, called at pact-core/Pact/Core/IR/Desugar.hs:323:8 in pact-core-0.1-inplace:Pact.Core.IR.Desugar
      Use -p '/ops.repl/' to rerun this test only.
    lambda.repl:      FAIL
      Exception: unimplemented
      CallStack (from HasCallStack):
        error, called at pact-core/Pact/Core/IR/Desugar.hs:323:8 in pact-core-0.1-inplace:Pact.Core.IR.Desugar
      Use -p '/lambda.repl/' to rerun this test only.
  Lexer and Parser Tests
    lexer roundtrip:  OK
        ✓ <interactive> passed 100 tests.
    parser roundtrip: OK (1.13s)
        ✓ <interactive> passed 1000 tests.