Merge #19454: tools: .clang-format compat with clang versions < 9

b9253c7 tools: clang-format 6 compatibility (Jon Atack)

Pull request description:

  Our `.clang-format` settings inadvertently lost compatibility with Clang versions < 9 in #19095, including for Debian stable. This patch returns compatibility in the interim until the distros update. See discussion from bitcoin/bitcoin#19095 (comment).

ACKs for top commit:
  MarcoFalke:
    Approach ACK b9253c7 , haven't tested

Tree-SHA512: 4af541a195f48d84ffb80e23aaefb624c66bc78f087c8d92b4af5a654420b69fedf25272c6e4fde2688ff88412d306b7a990ce1e15d8b24180374c625a253fb6

Author: fanquake

src/.clang-format

@@ -3,7 +3,6 @@ AccessModifierOffset: -4
 AlignAfterOpenBracket: true
 AlignEscapedNewlinesLeft: true
 AlignTrailingComments: true
-AllowAllArgumentsOnNextLine : true
 AllowAllParametersOfDeclarationOnNextLine: true
 AllowShortBlocksOnASingleLine: false
 AllowShortCaseLabelsOnASingleLine: true