Consolidate sample utility functions

Extend sample utility functions to support multiple inputs, so
simple_vec_mul can use the same utility functions.

Move the large barcode_float executable out of BUILD_WITH_SPRINGBOK
configuration

Move the input buffer allocation to a separate function so it can be
skipped if the buffer is allocated elsewhere, e.g., load from the
c_embedded data file.

Fix stack size for some models.

Change-Id: I954436bbb19d9707f64d6b1a252e39ddcfa3f7b9