Failing tests for 'source' with arguments.

This is a minor cleanup of tests written by BatmanAoD.

Co-authored-by: BatmanAoD <BatmanAoD@users.noreply.github.com>

spec/builtins.test.sh

@@ -156,6 +156,39 @@ echo status=$?
# OK bash stdout: status=2
# OK dash stdout: status=127

### Source with arguments
. spec/testdata/show-argv.sh foo bar  # dash doesn't have source
## STDOUT:
show-argv: foo bar
## END
## N-I dash STDOUT:
show-argv:
## END

### Source from a function, mutating argv and defining a local var
f() {
  . spec/testdata/source-argv.sh              # no argv
  . spec/testdata/source-argv.sh args to src  # new argv
  echo $@
  echo foo=$foo  # defined in source-argv.sh
}
f args to func
echo foo=$foo  # not defined
## STDOUT:
source-argv: args to func
source-argv: args to src
to func
foo=foo_val
foo=
## END
## N-I dash STDOUT:
source-argv: args to func
source-argv: to func
func
foo=foo_val
foo=
## END

### Exit out of function
f() { exit 3; }
f

spec/testdata/show-argv.sh

@@ -0,0 +1,2 @@
# File that can be sourced
echo show-argv: $@

spec/testdata/source-argv.sh

@@ -0,0 +1,7 @@
#!/bin/bash

echo source-argv: $@
# 'shift' will only apply to the args of 'f()' when no new args are provided.
# This can mutate the "caller's" arguments array!
shift
local foo=foo_val

test/spec.sh

@@ -268,7 +268,7 @@ if_() {
}

builtins() {
  sh-spec spec/builtins.test.sh --osh-failures-allowed 1 \
  sh-spec spec/builtins.test.sh --osh-failures-allowed 3 \
    ${REF_SHELLS[@]} $OSH "$@"
}