Merging r372281:

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r372281 | serge_sans_paille | 2019-09-18 17:54:40 -0700 (Wed, 18 Sep 2019) | 8 lines

Initialize all fields in ABIArgInfo.

Due to usage of an uninitialized fields, we end up with
a Conditional jump or move depends on uninitialised value

Fixes https://bugs.llvm.org/show_bug.cgi?id=40547

Commited on behalf of Martin Liska <mliska@suse.cz>
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