add getEnclosingBlock for Go

[Lslightly]

codeql/go/ql/lib/semmle/go/AST.qll

Lines 77 to 85 in 6fa6093

	/** Gets the parent node of this AST node, but without crossing function boundaries. */
	private AstNode parentInSameFunction() {
	result = this.getParent() and
	not this instanceof FuncDef
	}
	/** Gets the innermost function definition to which this AST node belongs, if any. */
	pragma[nomagic]
	FuncDef getEnclosingFunction() { result = this.getParent().parentInSameFunction*() }

In rust and cpp, getEnclosingBlock is supported as shown by search result. Would Go support this?

  /** Gets the parent node of this AST node, but without crossing block boundaries. */
  private AstNode parentInSameBlock() {
    result = this.getParent() and
    not this instanceof BlockStmt
  }

  /** Gets the innermost block statement to which this AST node belongs, if any. */
  pragma[nomagic]
  FuncDef getEnclosingBlock() { result = this.getParent().parentInSameBlock*() }