I think the ח should have a compound sheva (segol + sheva) under it, just as is the case in הֶחֱרִים, which means to destroy. Similarly, הֶחֱרִישׁ (to be quiet). So, you would pronounce הֶחֱלִיט as hekhelit, not hekhlit.
Also, the "compound" one is intended to ease pronunciation. In the past (some 2000 years ago, for centuries) ח was pronounced like Arabic ح and was hard to pronounce with "regular" schwa. Modern Hebrew speakers pronounce ח mostly like خ and have no problem with schwa (zero vowel) for خ so החליט is often pronounced with "regular" schwa.