[Task]: Introduce tooling support for check-on-fail-expr

[prakanth97]

Description

Refer :- ballerina-platform/ballerina-spec#1197

Syntax: check E on fail x => F

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[prakanth97]

Below are few example use cases.
Case 1:

function returnError1() returns error? {
    return error("Something went wrong");
}

public function main() returns error? {
    check returnError1() on fail e => error("Custom error", e);
}

Case 2:

function returnInt() returns int => 3;

// Can be declared in module variable definition
int val2 = check returnInt() on fail e => error("Error occurred", e);

function testCheckedOnFailExprReturnsValue() {
    // ternary expr
    int val = check returnInt() on fail e => error("Error occurred", e) is int ? 1 : 0;
}

Case 3:
According to this ballerina-platform/ballerina-spec#1197 (comment) below case also valid.

function testCheckedOnFailExprReturnsValue() {
    int val = check returnInt() on fail e => err(e);
}

function err(error e) returns error {
    return error("Error occurred", e);
}

[prakanth97]

With this #41079 PR compiler changes will be added

[KavinduZoysa]

Closing this issue because this feature is on hold.