Add SQL:2023 non-static method invocation

[martint]

Depends on #29385.

Description

SQL:2023 specifies <method invocation> — expr.method(args) — as a sibling of
<static method invocation>. Where T::method(args) namespaces a function under a
type, expr.method(args) dispatches on the receiver's type and passes it as the
implicit self argument.

This change introduces the syntax and a new @InstanceMethod SPI annotation.
Functions tagged with @InstanceMethod register with a receiver type taken from
their first @SqlType parameter and become callable only as expr.method(args).
A plain method(args) call cannot resolve to an instance method, mirroring the
static-method namespace separation introduced in #29385.

The receiver expression form (expr).method(args) parses unambiguously as a method
call. The bare A.B(args) form (where A is in scope as a column) keeps parsing
as a routine invocation, but per SQL:2023 6.3 Syntax Rule 2 the analyzer treats it
as a method invocation when one applies, falling back to function resolution
otherwise.

Example:

@ScalarFunction("char_length")
@InstanceMethod
@SqlType(StandardTypes.BIGINT)
public static long varcharCharLength(@SqlType(StandardTypes.VARCHAR) Slice self) { ... }

SELECT ('hello').char_length();                            -- 5
SELECT s.char_length() FROM (VALUES VARCHAR 'hi') t(s);    -- 2

Release notes

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# SPI
* Add `@InstanceMethod` annotation to register a scalar function as a non-static
  method of its receiver type, invocable via `expr.method(args)`.