`FastaSequenceIndexCreator` cannot create an index for FASTA files with multiple empty lines at the end of the file

[nvnieuwk]

When trying to use this FASTA file (genome_no_index.fasta.txt, remove the .txt extension before use. github didn't allow me to upload it otherwise) in the following function:

FastaSequenceIndexCreator.create(Paths.get('<path-to-fasta>'), true);

I receive this error:

java.lang.StringIndexOutOfBoundsException: String index out of range: 0
	at java.base/java.lang.StringLatin1.charAt(StringLatin1.java:48)
	at java.base/java.lang.String.charAt(String.java:1515)
	at htsjdk.samtools.reference.FastaSequenceIndexCreator.buildFromFasta(FastaSequenceIndexCreator.java:130)
	at htsjdk.samtools.reference.FastaSequenceIndexCreator.create(FastaSequenceIndexCreator.java:67)

After some debugging, I found that the issue is the two empty lines at the end of the file. It all works fine if I remove the second empty line, but it would be better if the function could work with these files instead of having to manually check every FASTA file.