Integrate known fixes for PROPACK problems

[asl]

PROPACK code is known to contain some bugs that may lead to out-of-bounds memory reads and corresponding problems.

You may want to integrate the following two commits that fixes them (note that these are for double version, so, they need to be ported to other variants and implementations):

1. https://github.com/asl/svd/commit/ac3f496cf337f59c7bb6037a772111a902e55cee
2. https://github.com/asl/svd/commit/b6f2c09590b84d2112f7e1cfdd924ae8ecbb7283