Revert "tests/utils/utils.sh: quote command name when running it"

Revert "tests/utils/utils.sh: quote command name when running it"

This reverts commit e612f2daa6b262796ca0750754142f0abd686f1d.

I believe that we want to do word splitting in these cases.  My
`$BT_TESTS_CC_BIN` is "ccache gcc".  Without word splitting, I get:

    /home/smarchi/src/babeltrace/tests/utils/utils.sh: line 431: ccache gcc: command not found

Change-Id: I7443dbcf1a45672cf4c7fcb7e15e94e83e85a832
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Reviewed-on: https://review.lttng.org/c/babeltrace/+/11766
Tested-by: jenkins <jenkins@lttng.org>
Reviewed-by: Philippe Proulx <eeppeliteloop@gmail.com>