Spec tests for the last glob parser commit.

- Adjust the number of allowed failures, since ${x//[a-z]/_} now works
  -- i.e. globs with a character class.
- Verify that another hard case now works.

spec/var-op-other.test.sh

@@ -104,6 +104,13 @@ echo ${s//[[:alpha:]]/y} ${s//[^[:alpha:]]/-}
# N-I dash status: 2
# N-I dash stdout-json: ""

### Replace hard glob
s='aa*bb+cc'
echo ${s//\**+/__}  # Literal *, then any sequence of characters, then literal +
# stdout: aa__cc
# N-I dash status: 2
# N-I dash stdout-json: ""

### Pattern replacement ${v/} is not valid
v=abcde
echo -${v/}-

test/spec.sh

@@ -409,7 +409,7 @@ var-op-test() {
}

var-op-other() {
  sh-spec spec/var-op-other.test.sh --osh-failures-allowed 2 \
  sh-spec spec/var-op-other.test.sh --osh-failures-allowed 1 \
    ${REF_SHELLS[@]} $OSH "$@"
}