`loadtxt` CI failure

Description

While testing stdlib I noticed loadtxt still fails sometimes in the CI.

Thanks to the recently added error messages, we now see:

 loadtxt: error <Bad real number in item 1 of list input> reading 6 values from line 1 of example.dat.
ERROR STOP

example.dat however only has 2 columns (not 6), but it has 6 total values:

stdlib/example/io/example.dat

Lines 1 to 3 in 6ec8cd0

    
           1.00000000E+00  1.00000000E+00 
        
           1.00000000E+00  1.00000000E+00 
        
           1.00000000E+00  1.00000000E+00

so the issue must lay in the number_of_columns function.

Expected Behaviour

No test should fail

Version of stdlib

0.7.0

Platform and Architecture

CI - ubuntu + gcc

Additional Information

No response

	1.00000000E+00 1.00000000E+00
	1.00000000E+00 1.00000000E+00
	1.00000000E+00 1.00000000E+00