[opt] merge filters on composite primary keys in plan (cp to 1.2-dev)

[aunjgr]

for a composite primary key (a, b), we merge multiple filters into one, i.e.:

• a = 1 and b = 2 => cpk = serial(1, 2)
• a = 1 => prefix_eq(cpk, serial(1))
• (a = 1 and b = 2) or (a = 3 and b = 4) => cpk in [serial(1, 2), serial(3, 4)]
• (a = 1) or (a = 2 and b = 3) => prefix_in(cpk, [serial(1), serial(2, 3)])

Approved by: @m-schen, @badboynt1, @XuPeng-SH

What type of PR is this?

• API-change
• BUG
• Improvement
• Documentation
• Feature
• Test and CI
• Code Refactoring

Which issue(s) this PR fixes:

issue #14515

What this PR does / why we need it:

for a composite primary key (a, b), we merge multiple filters into one, i.e.:

a = 1 and b = 2 => cpk = serial(1, 2)
a = 1 => prefix_eq(cpk, serial(1))
(a = 1 and b = 2) or (a = 3 and b = 4) => cpk in [serial(1, 2), serial(3, 4)]
(a = 1) or (a = 2 and b = 3) => prefix_in(cpk, [serial(1), serial(2, 3)])