Speedup Dirichlet BCs for deactivated subdomains

When the transposed matrix is created the zero entries are omitted in its sparsity pattern, which is fine if all rows/columns have at least one value. In case of deactivated subdomains the local assemblers are not run and the transposed matrix lags the required space to set the diagonal values resulting in costly reallocations.

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changed milestone to %6.4.1

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• 04547628...deb816da - 21 commits from branch ogs:master
• fe02b3ed - [MaL] Allocate space for diagonal values.

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• d27ffa06 - [MaL] Allocate space for diagonal values.

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mentioned in commit 9d496674

merged

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