Allow leading whitespace in input parameters

[brryan]

PR Summary

Currently, input parameters are read incorrectly. For example,

<block>
 var = 1.0

will read var as = 1.0, which when called with GetReal will cast to 0.

This PR fixes a bug where the length of the name was incorrectly calculated if leading whitespace was present in the input parameter file.

PR Checklist

• Code passes cpplint
• New features are documented.
• Adds a test for any bugs fixed. Adds tests for new features.
• Code is formatted
• Changes are summarized in CHANGELOG.md
• CI has been triggered on Darwin for performance regression tests.
• Docs build
• (@lanl.gov employees) Update copyright on changed files

[brryan]

BTW I tested this by adding a leading space character to tlim in the advection example

[pgrete]

LGTM
How about also adding the one-line test you mention (adding a space to one of the examples input files called by the test suite)?

[brryan]

LGTM How about also adding the one-line test you mention (adding a space to one of the examples input files called by the test suite)?

Good idea @pgrete, done (I changed tst/regression/test_suites/advection_performance/parthinput.advection_performance to check for both space and tab characters)