arrow

GH-38715: [R] Fix possible bashism in configure script (#38716)


### Rationale for this change

The CRAN incoming check for 14.0.0 is failing with a NOTE about a possible bashism

### What changes are included in this PR?

One `test -a` usage was replaced with `&&`.

### Are these changes tested?

Yes (via crossbow, below)

### Are there any user-facing changes?

No
* Closes: #38715

Authored-by: Dewey Dunnington <dewey@fishandwhistle.net>
Signed-off-by: Dewey Dunnington <dewey@fishandwhistle.net>