jsgen: assertions fail in sum types

[gchumillas]

Describe the bug

Assertion fail in sum types.

Reproduction Steps

Write a small main.v app:

type Type0 = string | int

fn main() {
	foo := Type0('')
	assert foo == Type0('')
}

Transpile to JS and execute it:

v -b js main.v
node main.js

Output:

FAIL: fn main.main(): assert foo == Type0('')

Expected Behavior

Assertion should be passed.

Current Behavior

Assertion doesn't pass.

Possible Solution

No response

Additional Information/Context

No response

V version

V 0.4.10 d433835

Environment details (OS name and version, etc.)

V full version	V 0.4.10 dead5e6.d433835
OS	macos, macOS, 15.4.1, 24E263
Processor	8 cpus, 64bit, little endian, Apple M1 Pro
Memory	0.15GB/16GB
V executable	/Users/gonzalo/Projects/Personal/v/nv/v
V last modified time	2025-05-17 21:20:55
V home dir	OK, value: /Users/gonzalo/Projects/Personal/v/nv
VMODULES	OK, value: /Users/gonzalo/.vmodules
VTMP	OK, value: /tmp/v_501
Current working dir	OK, value: /Users/gonzalo/Projects/Personal/v/nv
Git version	git version 2.39.1
V git status	weekly.2025.20-13-gd433835a
.git/config present	true
cc version	Apple clang version 17.0.0 (clang-1700.0.13.3)
gcc version	Apple clang version 17.0.0 (clang-1700.0.13.3)
clang version	Apple clang version 17.0.0 (clang-1700.0.13.3)
tcc version	tcc version 0.9.28rc 2024-02-05 HEAD@105d70f7 (AArch64 Darwin)
tcc git status	thirdparty-macos-arm64 e447816
emcc version	N/A
glibc version	N/A

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[huly-for-github]

Connected to Huly®: V_0.6-22875