A.init.field initialization ignores C++ field initializers

[timotheecour]

these fail currently:

static assert(A.init.b==10); // instead of 0 static assert(A.init.c==0); // instead of isNaN(A.init.c)

see test case in: https://github.com/Syniurge/Calypso/blob/documentation/calypso_semantics.md#field-init