Fix two issues with ipopt output parsing

[AlexGisi]

Fixes # .

Minor changes to IPOPT output table parsing.

Summary/Motivation:

The IPOPT output table can look like:

2121r-3.0297310e+03 2.70e-01 1.00e+03  -0.6 0.00e+00    -  0.00e+00 2.77e-07R  6
2122r-3.0144871e+03 9.46e-02 1.00e+03  -0.6 6.80e+03    -  4.34e-03 2.24e-03f  1
2123 -3.0145760e+03 9.46e-02 2.28e+02  -1.7 4.56e+02    -  6.14e-03 1.95e-04f  1
2124 -3.0145339e+03 9.46e-02 9.09e+04  -1.7 9.98e+02    -  5.13e-02 4.23e-05h  1

Notice there is not space between the first two columns. This PR notices and parses this correctly.

Also, according to https://coin-or.github.io/Ipopt/OUTPUT.html, capital 'S' is a valid alpha_pr tag, so this PR adds it as such.

Changes proposed in this PR:

• Handled when first two columns get squished
• Added 'S' to _ALPHA_PR_CHARS

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[AlexGisi]

This was addressed yesterday in #3738